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View Full Version : Hanging rev 250r air cooled passed leak down test



knipfeldustin
05-15-2014, 01:58 PM
What could be cause of death rev ?

barnett468
05-15-2014, 02:17 PM
.
Howdy!

http://t3.gstatic.com/images?q=tbn:ANd9GcQxr9P5OYMQvRhaWZ5QfBVTS7isj4zCS JQ6Ku1TmxO1HY-ScDvHod7NuYM


We need more info to best help you.


Are you 1,000% positive the test was done accurately?

Did you try to move the ends of the crank up and down during the test or ever to see if it has excessive bearing wear?

Exactly what are the conditions under which it happens?

Does it always happen?

Does it occur while you are riding or only when the slide is full closed like when you stop riding for a minute and just let it idle?

Are you 1,000% sure the slide is going all the way to the stop screw every time?

Are you 1,000% sure the throttle cable always has freeplay with the throttle closed and is not ever binding, getting pinched or sticking etc.?

About how high does it rev when this occurs?

How does it run?


Look at the slide and see if the chrome has worn away exposing the brass. An excessively worn slide can cause an irregular or high idle, but I've never heard of one causing a death rev.

knipfeldustin
05-15-2014, 02:30 PM
Did accurate leak down test yes. Also compression tested. It occurs when after riding at top end speed any gear three and above for a period of more than a minute or two. Bike fails to come back down from rpm. Continues to do so after kill switch removed for approximate 30 sec. I believe it is doing so because of a lean issue. Jetted out everything a few days ago and chopped plug and everything looks good nice cardboard brown ring. Bike starts runs and idles great besides this. Inspected carb and cable everything seems to be ok. Carb is 38 mm mikuni vm

barnett468
05-15-2014, 04:39 PM
Howdy!

http://t3.gstatic.com/images?q=tbn:ANd9GcQxr9P5OYMQvRhaWZ5QfBVTS7isj4zCS JQ6Ku1TmxO1HY-ScDvHod7NuYM



Continues to do so after kill switch removed for approximate 30 sec.It keeps running with NO ELECTRICITY?

If so, do not let it do this EVER.

How much choke does it when you first start it?

What is the outdoor temp where you first start it?

what is the compression?

Have you checked the timing or changed it from stock?

How far out from full in is the fuel mix screw?

what mods are done?

what octane gas are you using?

do you ever hear it "ping" while riding, especially when first accelerating?

what is your spark plug number?


i would spray FLAMMABLE carb cleaner using the long nozzle gently around the intake boot at idle. if the rpm goes up you have a leak.

if you have no air leak try a 1 step colder plug.

i might go up 1 on the main and pilot for now also until we can narrow the source of the prob down.

barnett468
05-15-2014, 04:42 PM
PS - On that bike, the timing is only adjustable if it has an aftermarket kit on it, but it's still possible for it to be off, especially if the flywheel pin is sheared etc..

knipfeldustin
05-15-2014, 04:49 PM
Yes it kept running after I pulled the killswitch. It has dg head with dg porting, roost factory silencer, expansion pipe is aftermarket not sure who by. Carb is 38mm. I never have to choke it. Outdoor temps here are mid 60-70 f . Compression tested out at 170. Haven't looked at or touched timing. No pinging noises running pump gas anything between 87-93 octane depending on where I buy. Running stock plug b9es or something like that can't remember off the top of my head. I have tried the starting fluid test and no leaks were found. I just recently went from a 380 main down to a 370 main because it seemed fuel heavy in the low gears and this seemed to help the dogginess. I did not build this motor I purchased this way definitely a top end bike pulls hard 3rd-5th

knipfeldustin
05-15-2014, 04:53 PM
Air fuel screw is 1.5 turns out. I've printed and read the 20 page tuning manual on these carbs and have checked and measured everything relatable. Checked float levels and made sure everything was in tolerances. I assume with no air leaks it would be a carb issue but I have found nothing considering just getting a Keihin off an 86 or an air striker 36mm or so

knipfeldustin
05-15-2014, 04:58 PM
Has a uni two stage filter with an old school roost factory air box

barnett468
05-15-2014, 05:10 PM
hello;

a new carb will not help you since your bike runs with no electricity.

i would stick with 93 octane for now.

if yiu are using a cheap chinese 20.00 compression gauge, it can easily be off 20 lbs to either side. this means that you might have 190 compression which means you might need race fuel even though you can not hear it ping. not all detonation is audible.

if the gauge is right it "should" be fine with 93.

did it do this with the 380 main jet?

i might also try the 380 with race gas or half race gas half 93.

i would stiill try a 1 step colder plug. its cheap easy and fast.

still check the timing. if it is adjustable, then retard it a hair.


would t170 rit is
i woy

srb should not help you unless the s

knipfeldustin
05-15-2014, 05:30 PM
mixing fuels of different octane doesn't actually "mix" the fuels, they have different individual specific gravities that basically allow them to separate such as water with different levels of salinity will do when mixed. My idea for a new carb was based on that I believe somehow extra air is being allowed into cylinder and causing the cylinder to "starve" itself which causes the engine to run extra revolutions after deenergizing it. I have nothing to prove its the carb just my assumption as it was the only part not included in the leak down test ??? I will look into timing as I haven't yet .......what I don't understand is why it only does this after I get to the top end of the rpm level of the motor, if I stay half throttle it will not do this just when I run it wide open at the top end it just refuses to come back down, sometimes if I let off throttle completely and shift down through gears this will pull it down but not always. I never really ran it wide open with the 380 jet just because I didn't feel it was running correctly. I appreciate your help !

sick85crownvic
05-16-2014, 07:47 AM
It definitely sounds like the combustion chamber is getting hot after a long WOT blast...the motor should not run 30 seconds on it's own after the killswitch is pulled...it's indicative of something in the chamber glowing hot causing it to "diesel". No restrictions in the fuel hose supplying the carb? My thinking is that even though it sounds/feels good everywhere else, that during a long top-end charge, it may be starting to lean out a hair causing the combustion temp/EGT's to spike.

Good luck,
Don

knipfeldustin
05-16-2014, 08:24 AM
I completely agree with you don. I'm am just simply out of ideas as to the cause I put a new fuel line and filter on when the issue started thinking what you were but to no avail. I'm not sure if needle adjustment or replacement could cause / fix the issue as I'm not too familiar with these finicky mikuni carbs. Almost makes me wonder if porting could be too aggressive also? I'm going to try to race this sat at sikeston ...going up two jet sizes ill run it in practice and if it continues may have to ride back up bike and open up top end to see what I have

El Camexican
05-16-2014, 08:58 AM
It sure sounds like you have an air leak, maybe one that exposes itself only when subject to high heat from the top end runs? Aside from that have you checked the flow of fuel from your tank to your carb? Perhaps if it is badly plugged up you could be running out of fuel on a top end run and then the combination of having run it lean (hot) and a very low amount of fuel in the bowl could cause the revs to go up.

Do the RPMs vary up and down at all when it’s screaming?

atc300r
05-16-2014, 09:40 AM
PS - On that bike, the timing is only adjustable if it has an aftermarket kit on it, but it's still possible for it to be off, especially if the flywheel pin is sheared etc..The oem stator timing on the 81-84 250r is adjusable. Check your fuel tank gas cap vent to see if its working properly.You should beable to blow threw it.

barnett468
05-16-2014, 12:16 PM
.
Howdy!

http://t0.gstatic.com/images?q=tbn:ANd9GcTDheK_NT7A9cIdJnV_1Pg7lGbLDWNu5 AVQnY60FToKElt_Wip72n1nHA


You’re welcome, you have an interesting prob and I for one am very curious to know what it is.



I'm am just simply out of ideas….See post 4 and 9.




as to the cause I put a new fuel line and filter on when the issue started thinking what you were but to no avail. I'm not sure if needle adjustment or replacement could cause / fix the issue as I'm not too familiar with these finicky mikuni carbs.Mikunii carbs are one of the least finicky carbs on the planet.




Almost makes me wonder if porting could be too aggressive also?Porting has nothing to do with it, 0 nada, zilch.




I'm going to try to race this sat at sikeston ...going up two jet sizes ill run it in practiceI would not do that. If you do not have time to do all the tests I and others have suggested I would do the following as a hopeful temporary fix.

Run a 10 plug. You may have to go back to the 9 but I doubt it.

Go up 1 on main.

Retard timing just a hair.

Do not lower the slide.

If you get your hands on some race gas mix it 50/50 or go straight and go up 1 more on he main.




if it continues may have to ride back up bike and open up top end to see what I havelook for marks in the combustion chamber. small sharp points can heat up enough to ignite the gas.

I can tell you this. It keeps running because there is enough heat in your cylinder to ignite the gas as another mentioned above. This is the reason I suggested the colder plug. This will reduce the temp of the plug by around


From Champion.

"In identical spark plug types, the difference from one full Heat Range to the next is the ability to remove 158 deg f to 212 deg f from the combustion chamber."

http://www.championsparkplugs.com/learning-center/article/205/i-have-slightly-modified-my-motor---do-i-need


Nothing you have said indicates to me exactly why it is running hot.

Please do all the things I and others suggest even if you might think they are unnecessary.


CARB – By all means try one if you want, however, if you read your own info you can see that there is not one single but of info that suggests to me it is the carb, however, certainly try one if you want.

One of the things you can do is to back out the idle screw until the slide closes all the way. Do NOT let the slide go all the way down immediately after going wot, or you might damage the engine. Let it down close to 0 for at least around 3 seconds first. This is only a temporary test.

There are thousands of people that have run and are still running the old school VM style carbs. Virtually every single race and Championship that was won in the 70’s had one. All the of the Team Green riders had them and won many races and Championships with one on their Tecate's..."The fastest production 3 wheeler in the world.".

See a Mikuni VM on Jimmy Whites Honda slaying, multi Championship Winning bike below.

http://atvscene.com/images/white3wheeler.jpg



SLIDE – If the chrome is worn off so you can see the brass in some areas this might contribute to the problem, but this typically simply creates an erratic or slightly high idle prob.


MIXING DIFFERENT OCTANES – I know a little about about gasoline but certainly not everything, you may know more than I, however I not only know that there is NO ZDDP in it but can also guarantee you that if for example, you mix 87 with 93 it will increase the combined fuels resistance to detonation. Zillions of people have done this. Many people here have done this as well as mixing pump gas with race gas for years and their engines have suffered no ill effects from doing so.

I know the people at Lucas where I occasionally buy race gas and both they and VP fuel will also tell you the same thing, however, their standard answer is “We suggest you do not do that”. They will never say it does not reduce the combined fuels resistance to detonation. I am aware that different fuels have different specific gravities, but I can assure you that if you mix them together, the “lighter” gas does not sit on top of the “heavier” gas like oil does on still water. I have actually had water in an engine crankcase before and i can assure you that when i drained it, the oil pump had homogenized it quite well.

This being said, I prefer not to mix fuels.

The reason I want you to try it if it’s possible, is because the racing fuel might run a bit cooler. It does not mean that if it helps you need to run it all the time.


OMG…it’s a talking pig!
http://www.freesmileys.org/smileys/smiley-laughing025.gif (http://www.freesmileys.org/smileys.php)

atc300r
05-16-2014, 12:22 PM
If you can find it in your area use 91 octain or higher non-ethanol gas.

yaegerb
05-16-2014, 01:45 PM
I am with El...sounds like air is somehow getting in there. I am sure you already checked this, but are you sure the slide isn't hanging or throttle cable getting bound?

DohcBikes
05-16-2014, 02:17 PM
I just recently went from a 380 main down to a 370 main

And did it rev before you did this?

Maybe its too lean now when it get hot.

Even if this isnt it, i wouldnt lean out a bike because it "feels doggy", lean out a bike when the plug looks rich.

+3 on air leaks.

Mixing octanes works, I mean, its real, people do it.

barnett468
05-16-2014, 03:08 PM
And did it rev before you did this?

Maybe its too lean now when it get hot.

Even if this isnt it, i wouldnt lean out a bike because it "feels doggy", lean out a bike when the plug looks rich.

+3 on air leaks.

Mixing octanes works, I mean, its real, people do it.




. . . . . . . http://t2.gstatic.com/images?q=tbn:ANd9GcR5o7SoSoMjblKw9_dE_A2Tx7jS1px4p qVrkgs-d9bUqY_Wo6mzJkAceA

http://www.beercankorner.com/graphics/tecate0201.GIF

http://www.totalwine.com/_static/webupload/731/2_2730175_3_3.jpg

barnett468
05-16-2014, 03:23 PM
.


Mixing octanes works, I mean, its real, people do it.

+1...Mixing octanes works just fine. A lil Cap'n Morgans and a Tecate...The fastest production 3 wheel...oh sorry...La cerveza mas fina! . How'd I do El?


http://www.totalwine.com/_static/webupload/731/2_2730175_3_3.jpghttp://www.beercankorner.com/graphics/tecate0201.GIF



OMG...What a dumba__!
http://www.freesmileys.org/smileys/smiley-laughing025.gif (http://www.freesmileys.org/smileys.php)

knipfeldustin
05-16-2014, 03:58 PM
I can blow through my cap vent and feel air coming out inside of cap when removed.

barnett468
05-16-2014, 04:02 PM
I can blow through my cap vent and feel air coming out inside of cap when removed.That's good, you don't want it plugged.

knipfeldustin
05-16-2014, 04:05 PM
Mixing octanes works, I mean, its real, people do it.[/QUOTE]

People do alot of things. All it does is create different detonation points in your cylinder causing different temperatures in different areas putting unnecessary wear and tear on an engine cylinder for no specific gain. People do it under the assumption it creates a different octane level which it simply does not. Fuel is fuel sure it will burn no matter what u put in it....mix fuel in water and it still ignites.

knipfeldustin
05-16-2014, 04:07 PM
+3 on air leaks

?????

knipfeldustin
05-16-2014, 04:16 PM
I will try out some of your suggestions this weekend and see what I can come up with. I appreciate the help. I do not know if it reved like this with the 380 main as I never rode it top end much as it was so crappy running in the lower end I just parked it until I had time to rejet. Doggy isn't necessarily the word to describe why I rejetted.... The engine was acting like it was flooded out. My plug was showing fuel heavy. As I stated I haven't had this one long enough to get to know it real well yet just trying to debug .....race is cancelled so no riding this weekend

DohcBikes
05-16-2014, 05:18 PM
+3 on air leaks

?????
As in, I third the recommendation to not rule out the possibility of air leaks. Its a common way to say, "what they said" on a forum.

As for mixing octanes, which fuels mix well, hot spots and such, as you may know, theres even more to it than you are describing, yet, it gets done with good results in the real world every day, despite the scientific explanation.

knipfeldustin
05-16-2014, 05:55 PM
That's a whole Lot of commas. ..... I get what your saying on the air leaks that has been my assumption from the beginning but passed leak down test twice so I'm looking for other ideas.

nicker71
05-16-2014, 06:38 PM
Just sell it.

knipfeldustin
05-16-2014, 06:41 PM
Get your checkbook out

DohcBikes
05-16-2014, 07:01 PM
Leak down test doesnt acount for air leaks between the carb and intake.

My opinion is that its lean, but im no scientist, and also, I have an abundance of commas, unlike many others, and im just trying to spread the wealth, you're :welcome:, and by the way, how much you selling it for?

knipfeldustin
05-16-2014, 07:34 PM
Yes I agree that's why I was thinking new carb because I have also leak tested the intake boot while running with starting fluid and no change in rpm. This leads me to believe if it is an air issue it has to be carb related. It could be something all together such as the things Barnett suggested I just haven't had a chance to test further yet.............................wouldn't sell for less $1600. Pretty much everything except frame handlebars and engine cases and forks are old school aftermarket.

yaegerb
05-16-2014, 07:36 PM
deleted, due to you already checking...LOL. I assume you are using fresh, high octane gas? What you are explaining sounds to me like a death rev which also occurs when you close the petcock and let the bowl drain. When there is more air than gas it will start accelerating RPM's......perhaps its was too lean on the main. Have you tried larger jets yet? 2 stroke bogging goes both ways...lean and rich (thanks Bryan ;))

knipfeldustin
05-16-2014, 07:40 PM
193653


Well maybe I can post pics

knipfeldustin
05-16-2014, 07:46 PM
Bryan I bought 2 lower jets and 2 higher. Started off at 380 main. Didn't even check pilot as it starts and idles great. Took down to a 370 and it felt the best overall to me and I ran a plug test and cut the threads off and plug looked good. I'm going to try a 390 jet tommorrow and see what that does. I'm also going to pick up a gallon of 110 leaded and try that. 170 is what the compression test said but if the gauges can be off as much as Barnett stated it may need the race gas. It's definitely pulls hard up top

knipfeldustin
05-16-2014, 07:53 PM
And what you described is exactly what it is doing Bryan, I believe I have 93 octane in it now

nicker71
05-16-2014, 07:54 PM
The power valve probably went bad

knipfeldustin
05-16-2014, 08:04 PM
193654


This is plug from the 370 jet test.

yaegerb
05-16-2014, 08:12 PM
No worries, but I am Brendon. The only reason I said thanks Bryan is because BKM (Bryan Melugin) taught me a few things last week. No worries though and yes try some race gas and some bigger mains and let us know how it works.

knipfeldustin
05-16-2014, 08:14 PM
Oh sorry bud. Appreciate the help !

sick85crownvic
05-16-2014, 09:04 PM
You can always send me the head and piston for mirror polishing! lol We've done this to a number of 2 stroke machines with great results as it significantly reduces the chances for detonation. I just did a YZ125 with some top secret port work and it now EATS 450F's. I love two strokes! Let us know how the jetting shenanigans go...a few weekends ago we went bat-crap crazy trying to get a blaster dialed in....owner cleaned his K&N air filter and while it was still wet, oiled it enough to cover 12 K&N filter services...this was done after it was brought in, as we were replacing reeds...once we figured that out and got everything set up, the jetting made a phenomenal difference...hoping you can get'er figured out sooner rather than later and we can all learn a little bit and you can get back on the track with it(and show up some Kawi guys! lol)

Good luck,
Don

YTZ drew
05-16-2014, 09:27 PM
To me that plug is still reading a tiny bit lean, but others may differ. Is it possible that what you initially thought was a rich plug was actually dark due to burning a little tranny fluid (bad drive end crank seal)? If the bearing is heating up and getting loose after a hard run, there would be your air leak. Also, why not pull the head off and check for a burr? Or, if you have access to one of those little inspection cameras, pull the exhaust and go looking in through the port. A burr or divot with a raised edge will definitely cause a hot spot.

knipfeldustin
05-16-2014, 09:59 PM
I hadn't thought of or heard of the tranny fluid burning ? Is this common ? First time I've dealt with this also so maybe I'm out of the loop
Eventually I'll tear into the engine and see what I've got goin I just want to rule out all the simple quick tests first.
Don do u offer porting or just the polishing service ?

El Camexican
05-16-2014, 10:03 PM
193654


This is plug from the 370 jet test.

That sure looks lean to me. How long did you use that plug for?

knipfeldustin
05-16-2014, 10:06 PM
Just for the test. Warmed bike up with a different plug. Pulled that plug out installed new plug (pictured) and and went wot through the gears til top of 5th immediately pulled killswitch and coasted to stop. Pulled plug and chopped threads.

danbur55
05-16-2014, 10:07 PM
Gonna ask a question more than offer any help. But is oil gas mixture any way relative to WOT runs vs say mid to low range? As I said don't know that much but curios if possible. Thanks

knipfeldustin
05-16-2014, 10:09 PM
You guys maybe correct about it looking lean I was told this was the color I was looking for but that's just someone's opinion .....anyone with pics of a properly jetted r plug ? We also tested my friends 2nd gen 300 and his plug was almost identical in color but the ring was wider (almost double) does the ring size on the plug tell you anything ?

El Camexican
05-16-2014, 10:17 PM
Mixing octanes works just fine. How'd I do El?
I’m not much of a beer guy, so when mixing octanes other than Pemex verde con roja I prefer to mix the two liquids shown and ignite them with one of these fat boys. Must suck to live under a regime that hates Fidel Castro so much they won’t let you enjoy two of life’s greatest pleasures.:rolleyes:
193656193657193658

El Camexican
05-16-2014, 10:26 PM
You guys maybe correct about it looking lean I was told this was the color I was looking for but that's just someone's opinion .....anyone with pics of a properly jetted r plug ? We also tested my friends 2nd gen 300 and his plug was almost identical in color but the ring was wider (almost double) does the ring size on the plug tell you anything ?
Forget the black around the rim, or any deposits, that comes with prolonged use. The light brown/tan on the plug on the right is a nice safe color. That guy might even be able to go down another size if he was racing for a living, but for me that is what I want my plug to look like when I finish a long trail ride.
193659

DohcBikes
05-16-2014, 11:28 PM
Post #49 for a lean bike. Jetting was changed, it now revs, plug looks lean etc....etc.....etc.....

Can we get some tuning changes in the mix here lol....something! I'm patiently (OK no that's out the window:D) waiting to see what going back to the original or *GASP* even richer jetting than you had will accomplish......

:beer

barnett468
05-17-2014, 09:02 AM
Howdy!

http://t0.gstatic.com/images?q=tbn:ANd9GcTDheK_NT7A9cIdJnV_1Pg7lGbLDWNu5 AVQnY60FToKElt_Wip72n1nHA

Post 50...do we win a prize? :w00t:

Billy Joe Billy Bob is a little sauced right now so he asked if I could help out.




I was thinking new carb because I have also leak tested the intake boot while running with starting fluid and no change in rpm. This leads me to believe if it is an air issue it has to be carb related.Based on your comments, it’s NOT the carb, no way, no how…NOPE. Based on your PLUG photo, the ONLY thing wrong with your carb, is the MAIN JET that is obviously too small.

Your carb is not getting hot at wot thereby causing it to get a temporary air leak that goes away after the engine cools slightly. You are missing the point, you should be able to hold the throttle WIDE OPEN then pull your ignition and it should STOP RUNNING unless something in the cylinder was hot enough to ignite the gas as I and around 50 other people have mentioned.
Like I said…if you want a new carb, buy one. It ain’t gonna fix your problem though but it will look awful pretty. http://www.freesmileys.org/smileys/smiley-laughing013.gif (http://www.freesmileys.org/smileys.php)




This is plug from the 370 jet test. 193654
Hey…that color looks perfect….for my Lexus… Go up as I and around 50 others suggested. 2 sizes max.

If it gets too rich, it will burble/sputter. This is when you can say it “runs like a dog”. It’s common to go down around 1 -2 sizes from the rich/sputtering point.

In other words, if you were to put like a 420 in it, it will gesticulate at high rpm’s for sure. Then you try a 410, 400, 390 etc., until the gesticulation is gone, then go down 1 minimum or 2 maximum from that point. This way you know you are not too lean for that elevation and air temp etc.. Jetting typically must be changed slightly based on varying conditions.




I hadn't thought of or heard of the tranny fluid burning ? Is this common ?You are not burning tranny fluid. Anyone that reads all the posts knows that because you did two leak down tests with no leaks.




Gonna ask a question more than offer any help. But is oil gas mixture any way relative to WOT runs vs say mid to low range?Scientific testing shows that as the rpm increases, the oil “migrates” through the engine faster. This means that 20:1 “acts” leaner at say 6000 rpm than it does at say 2000 rpm. Yes I know it makes no bleepin sense because it is still 20:1, however, in simple terms, this is what it does. This is why racers that run at high rpm all the time use more oil in their mix than a trail bike would.




hoping you can get'er figured out sooner rather than later and we can all learn a little bit and you can get back on the track with it(and show up some Kawi guys! lol) Good luck, Don

Yeah..."Good luck" is right cause yer gonna need it along with a boatload more horsepower if you think you're gonna beat this thing. :rolleyes:

http://atvscene.com/images/white3wheeler.jpg




Or even this, and it's completely stock!
The KAWASAKI TECATE...The fastest production 3 wheeler in the universe. Hoosier Daddy

http://www.quadpit.com/images/mags/stories/1986/tecate/51.jpg


You sir, have been served! ! !

http://t2.gstatic.com/images?q=tbn:ANd9GcTz7M5yPEM3Y0DYFPyxYsQdq9ogPLzXp FQ2LKYtPxLrA3zuqXBQJe66q8o


Holy cr_p…I gonna die laughin. People simply shouldn’t drink before they post. Ahhhh, ha, ha…
http://www.freesmileys.org/smileys/smiley-laughing025.gif (http://www.freesmileys.org/smileys.php)

El Camexican
05-17-2014, 09:17 AM
Gonna ask a question more than offer any help. But is oil gas mixture any way relative to WOT runs vs say mid to low range? As I said don't know that much but curios if possible. Thanks

Only that you need to use more oil if WOT is where you ride all of the time like say a road race bike VS a low speed trail rider. In theory adding more oil to each gallon of gas leans your engine out as the oil displaces fuel, but it is a negligible difference unless you were say jetted perfectly at 8,000’ of altitude using a 100 to 1 oil ratio and then one day you trailer your ride down to sea level and started running a 16 to 1 oil ratio with no other changes, but this particular problem has nothing to do with oil ratio or brand.

knipfeldustin
05-17-2014, 09:41 AM
I don't ask you to keep posting the same trailprotrailprotrailprotrailpro over and over that's your choice bud. I'm simply having conversations with more than one person here who all suggest different things. I believe I stated I would try jetting it up today it's now 8 am ............................whole lot of day left .......since the color ring on my plug is lean you say what color am I looking for ? Like I asked before does the size of the color ring mean anything?

sick85crownvic
05-17-2014, 10:19 AM
Don do u offer porting or just the polishing service ?

I really only do porting for local guys, so I can match the slope of the feed ramps to the transfer ports and make sure everything is good...but I'll polish stuff for anybody! lol

DohcBikes
05-17-2014, 10:57 AM
I don't ask you to keep posting the same trailprotrailprotrailprotrailpro over and over that's your choice bud. Hmmmmmm.....are you sure?

does the ring size on the plug tell you anything ?

Forget the black around the rim, or any deposits, that comes with prolonged use.

.....anyone with pics of a properly jetted r plug ?

193659

.......since the color ring on my plug is lean you say what color am I looking for ?
Like I asked before
does the size of the color ring mean anything?



This is huge discussion for a simple issue. There are several very knowledgeable people attempting to tell you to start making changes, because your bike is most likely running lean.

Talking about the specific gravity of a fuel molecule isnt gonna tune this bike.

Maybe if you hadnt started several threads complaining about how the site functions, people would be a touch more receptive.:D

On the other hand, you have an engineer, more than 2 bike technicians, and El Camexican (if you dont know then ya better get some schoolin) telling you how to start tuning the bike, but it seems that you are attemting to instead DISCUSS tuning the bike, or possibly even just allowing us to be in the presence of your knowledge.

Hopefully you arent the sensitive type, theres a lot of that going around.

Still looking forward to some results. Even if we are ALL wrong and its not the main jet you changed, then at least we have somewhere to go from there.

:beer:beer:beer:beer:beer

barnett468
05-17-2014, 11:10 AM
Howdy!

http://t0.gstatic.com/images?q=tbn:ANd9GcTDheK_NT7A9cIdJnV_1Pg7lGbLDWNu5 AVQnY60FToKElt_Wip72n1nHA



I asked before does the size of the color ring mean anything?Well one thing it means is that your plug only has a few minutes on it and the ring will simply grow a little larger and get progressively lighter toward the tip. That might sound confusing but I wouldn't concern myself with it because I do it a slightly different way.




since the color ring on my plug is lean you say what color am I looking for ?El Camexican posted a photo of plug colors in post 48. I am saying the upper part of the porcelain looks lean. The top of your porcelain will get a little darker after a few more hours, however, I and others can tell where it’s heading. A more accurate readings can be achieved after a minimum of around 20 minutes of slow and wot riding. I occasionally like to finish up after 30 minutes with a wot plug chop. Others do it differently.

After looking at over 100 plug photos, this is the best example I found. Imo, your plug should look very similar to the one on the right left after around 15 minutes of riding. After a few hours or more it should look like the one in the left or just a hair darker imo. After many days or more, it will likely look more like the one in El Camexicans photo.

I have personally only seen one plug with the threads chopped off. We did not do this in R and D and Racing dept never did this and Kawi has won a zillion races and a zillion Championships.


My point is, after you ride it slow and wot for around 30 minutes, I would want it to look darker than the one on the right. If it looks a hair darker than the one on the left after a few hours it is fine imo. if it looks noticeably darker, it is rich. The other point is, if your jetting was WAY off, I would expect you would hear some detonation/pinging or notice some performance problems like flat spots or burbling under acceleration etc., but you haven't mentioned anything other than "dogginess" which is a bit hard for some of us to interpret. .

http://i577.photobucket.com/albums/ss211/Off_Road/Dynoplugs3.jpg


OMG…The pig is talkin again!
http://www.freesmileys.org/smileys/smiley-laughing025.gif

DohcBikes
05-17-2014, 11:18 AM
Imo, your plug should look very similar to the one on the right left after around 15 minutes of riding. After many days or more, it will likely look more like the one in El Camexicans photo.http://www.freesmileys.org/smileys/smiley-laughing025.gif


I have personally only seen one plug with the threads chopped off. We did not do this in R and D and Racing dept never did this and Kawi has won a zillion races and a zillion Championships. http://www.freesmileys.org/smileys/smiley-laughing025.gif



but you haven't mentioned anything other than "dogginess" which is a bit hard for some of us to interpret. .http://www.freesmileys.org/smileys/smiley-laughing025.gif




OMG…
http://www.freesmileys.org/smileys/smiley-laughing025.gif

barnett468
05-17-2014, 11:28 AM
.
Howdy!

http://t3.gstatic.com/images?q=tbn:ANd9GcQxr9P5OYMQvRhaWZ5QfBVTS7isj4zCS JQ6Ku1TmxO1HY-ScDvHod7NuYM


Sorry...wrong photo. The one on the right is lean, the one on the left is ideal.


http://i577.photobucket.com/albums/ss211/Off_Road/ReedPlug1.jpg

OMG...

http://www.freesmileys.org/smileys/smiley-laughing025.gif (http://www.freesmileys.org/smileys.php)

knipfeldustin
05-17-2014, 02:22 PM
Like I said I appreciate the info and I have performed some of the tests you have suggested. As for the site sure i think it's ridiculous to post ten times after having been a member for almost three years common sense would tell you its not a spammer acct I had legit posts on my 350x .... I'm welcome to my opinion as much as you are yours. I was taught to jet this way I'm not pretending to say its right just how I was shown. As for the fuel issue no I'm not going to agree with your info, again you all are welcome to your opinion ill stick with what I know on this issue no reason to be upset because your opinion doesn't agree with mine if you don't like being called out for something you said that could "gasp" possibly be incorrect or is different then I'm sorry I can't help you there. This isn't a pissing contest so stop trying to turn it into one.

As for the tips provided I am working my way through them. I went up two jet sizes this morning and the issue remains this time as soon as I got to wot and tried to come back down it did it. I performed the starting fluid test to The intake boot while idling before this with no leaks. I appreciate the pics that helps. I'm going to relearn this plug stuff if my way is incorrect because I was taught if you don't chop the plug then you don't know what it's telling you and it's the only way I've done this in the past it has worked until now but if its incorrect ill try it your way .... I can't really ride it for 30min because after a few at wot its death revving. The bike ran about the same with the 390 jet as it did the 370 sputtered in the low end a bit about quarter throttle but cleaned up about half throttle in first and second. That is the biggest main jet I have currently...

After thought ....the bike didnt run long enough to get overheated before it occured this time as I didn't even have 5 min on it before the rev

It's a 45 min drive for me to get race fuel so ill test that out when I am going in that direction to pick some up.

I inspected the carb slide and it appears in good working condition without excessive wear.

My throttle cable is free and not frayed, I sprayed some lubricant inside it anyways to cover that issue.

I watched that my fuel filter stayed full of fuel while riding this morning and the line is new so flow is not an issue.

So as of now the trike has performed the same rev with a 370, a 380, (which is what was in it when I bought) and a 390 main jet.

I do not hear any pinging noises. honestly this is one of the quietest smoothest sounding air cooled motors I have ever listened too. I am not an expert obviously but have grown up on these.

I will continue to work on suggested tests and post back results as completed.

Again thanks for your help.

knipfeldustin
05-17-2014, 02:35 PM
193671

Slide pics

knipfeldustin
05-17-2014, 02:37 PM
193672

This side shows some brass at the top of slide but doesn't continue the length of slide

knipfeldustin
05-17-2014, 02:39 PM
using your words it was burbling under acceleration with the 390 jet in first and second gear quarter throttle if this helps with describing it better

El Camexican
05-17-2014, 03:37 PM
using your words it was burbling under acceleration with the 390 jet in first and second gear quarter throttle if this helps with describing it better

Your main jet has next to no effect on ¼ throttle opening operation. That would be your air screw, pilot jet and needle in that order. The main jet becomes the principal factor around ¾ throttle.

barnett468
05-17-2014, 03:41 PM
I'm going to relearn this plug stuff if my way is incorrect because I was taught if you don't chop the plug then you don't know what it's telling you and it's the only way I've done this in the past it has worked until now but if its incorrect ill try it your way.It is not wrong per se, it is just not the best way or maybe the only way that it should be tested. There is A lot MORE TO READING a plug then you might imagine. the color of the porcelain near the tip can tell something about a different throttle position ir rpm etcc. The electrode strap thells you things. the outer ring or end of the threads tells you something but in the end if you have a peefect looking plug and your bike runs like cr_p then you still need to jet it. Unfortunately it is NOT something that is a pefect science that you can put in a box. It is just a general guide. Timing, plug heat range and oil ratio etc affect plug color. I don't obsess about it. As I mentioned, Kawasaki...over 200 championships...never cut the threads off a single plug.... The one exception might be Rob Muzzie and the road race team but i don't know. I can also pretty much guess that Honda was not out there at Unadilla or Hangtown during a National, hackin the end of Marty Smiths plug either.





I went up two jet sizes this morning and the issue remains this time as soon as I got to wot and tried to come back down it did it.Did it burble/sputter at wot?

What does the new plug look like with the 390?





I performed the starting fluid test to The intake boot while idling before this with no leaks. I appreciate the pics that helps.no prob you're welcome, however, of course it's not caused by an air leak. Like I said...your bike runs with no electricity.





I can't really ride it for 30min because after a few at wot its death revving.then just ride it normally as long as you can while trying to avoid what ever causes the problem so you can get some time on the plug.





The bike ran about the same with the 390 jet as it did the 370 sputtered in the low end a bit about quarter throttle but cleaned up about half throttle in first and second.You did not previously say it sputtered with the 370. the main is contributing little to the sputtering at that position. It is mainly the needle and the pilot. If it starts with no choke then maybe go down 1 on the pilot jet.

YOU SHOULD TRY DROPPING YOUR NEEDLE ALL THE WAY DOWN. IF IT IS ONLY 1 OR 2 CLIPS FROM BEING DOWN IT WILL NOT HELP MUCH BUT TRY IT ANYWAY. IT SOUNDS TO ME LIKE YOUR NEEDLE JET MIGHT BE TOO BIG OR YOUR NEEDLE IS TOO SMALL IR THE TAPER IS INCORRECT.

IT IS POSSIBLE THE CHOKE HEIGHT OF THE JET NEEDLE IS TOO HIGH ALSO. You need to give us all the numbers off it. or just post a photo of it in the carb for now.

your slide might also be wrong. we need that number.





That is the biggest main jet I have currently...It is likely big enough imo.




After thought ....the bike didnt run long enough to get overheatedyes it did, this is why it runs with NO ELECTRICITY.

:beer

barnett468
05-17-2014, 03:52 PM
I would do the following also.

The following gas level test eliminates the need to check the float level and can be more accurate. It should also be done PRIOR to jetting.

GAS LEVEL - Check the actual gas level first by doing the following:

1. get a small 10” long piece of clear plastic tube.
2. connect it to the float bowl drain fitting.
3. hold it close to the carb with the open end even with the top of the carb.
4. open the gas valve on the tank and drain screw on the carb bowl.
5. the gas in the tube should be from even with the bottom of the main carb body to 3/16” below it. If it is outside this range, I would correct it.

If your gas level is high but you have plastic floats you might need a new float or possibly heat that one and bend it.

Also if the level is high it can cause big problems and you will likely never get it jetted properly.

knipfeldustin
05-17-2014, 11:58 PM
I stated this because the manual for this model carb stated main jet affects 1/4 to wide open throttle. The mikuni vm super tuning manual by mikuni is what I printed off the web for the info I have on the vm model carb.

knipfeldustin
05-18-2014, 12:13 AM
The bike runs great at wot throttle until you let off and then it immediately starts the insanely high rev crap and continued for 7 seconds today, I originally stated it did this for 30 secs which was a overestimate I'd say the longest it's continued to run was 15 secs max
. I did not pull the plug after riding with the 390 jet as I only got to third gear and went to downshift to turn and as soon as I clutched engine began overreving so I pulled kill switch to get it to stop.
In my post I didn't mean it sputtered with the 370 jet I meant it ran very similar to running the 390 and was just a little sputtering in the bottom spectrum of things with the 390 jet only.
I did happen to notice today when I pulled my slide that the needle is all the way down(clip in top position).

I will get some numbers and pics of everything in the morning.

I actually went through the steps of checking the floats according to the manual and they both measured correctly. I will still run your tube test tommorrow and see what happens.

barnett468
05-18-2014, 07:30 AM
.

It occurs when after riding at top end speed any gear three and above for a period of more than a minute or two. Bike fails to come back down from rpm. Continues to do so after kill switch removed for approximate 30 sec.

http://t1.gstatic.com/images?q=tbn:ANd9GcRKdzMjs6QCUkk5gCZ5v76_6Dw4b33sY e0dHTw_94kbjoa1RDHeNd79ylU

Heir Knipfeldustin.

Does it still run with no electricity with the 390 main jet when the high rev situation occurs?

1. Yes.

2. No.

3. I don't know because I did not try it.

:beer

barnett468
05-18-2014, 07:57 AM
The bike runs great at wot throttle until you let off and then it immediately starts the insanely high rev crap and continued for 7 seconds today,

http://t0.gstatic.com/images?q=tbn:ANd9GcTDheK_NT7A9cIdJnV_1Pg7lGbLDWNu5 AVQnY60FToKElt_Wip72n1nHA

Heir Knipfeldustin.

Did you lower the slide all the way and try it as Barn suggested earlier?

1. Yes.

2. No.

3. I don't know because I did not try it.




I only got to third gear and went to downshift to turn and as soon as I clutched engine began overreving so I pulled kill switch to get it to stop.
Did it stop immediately?

If not, how long did it run before it stopped?

Did it actually run with no electricity with the 390 main as you previously said?

1. Yes.

2. No.


If it stopped immediately, then we have cured your running with no electricity problem.


OMG...The pig is interrogating Knipfeldustin...Barn used the wrong photo..what a moron!
http://www.freesmileys.org/smileys/smiley-laughing025.gif (http://www.freesmileys.org/smileys.php)

knipfeldustin
05-18-2014, 08:59 AM
Yes.......

knipfeldustin
05-18-2014, 09:05 AM
No I have not tried lowering the slide yet. (Will do today)

No it did not stop immediately it continued to run for 7 seconds(with no electric) at extremely high rev after I pulled the kill switch with the 390 jet.

barnett468
05-18-2014, 09:31 AM
No I have not tried lowering the slide yet. (Will do today)ok, let us know but i'm not holding my breath for a positive result.





No it did not stop immediately it continued to run for 7 seconds(with no electric) at extremely high rev after I pulled the kill switch with the 390 jet.son of a "bleepin" "bleep". WTF is its prob?

Try a 10 heat range plug today too if you have access to one.

i would not do a ton more with the main until you try that unless you have a bigger main or can get one easily. i know you said all you have is a 390. based on everything, i really "think" that is large enough but in your case it appears that we need to throw the entire book at it which is nuts.

some race bikes can tend to run on after the electricity is stopped but that's typically because they run near the edge of destruction to try and gain that tiny edge in hp, however, this should never occur on a non pro race bike because there is no point in running near the edge.

there was a guy on here several months ago that had a run on prob after it was turned off. he finally removed his head and it looked like someone had taken a center punch and hit the combustion chamber a zillion times. this was actually caused by detonation.

around the tiny dents were very sharp raised pieces of metal. i don't remember if he sanded them out or got a new head but i think he sanded them and it fixed the problem.

your bike does not detonate/ping now but it might have before you owned it which might have created the same prob inside your chamber. the ocurrence you have now is actually called pre ignition. some call it "run on" or "dieseling" these two latter conditions occur AFTER the ignition is turned off. i have never seen them cause a high idle after wot.

knipfeldustin
05-18-2014, 09:52 AM
I live in the middle of no where so I won't be able to get a plug besides the stock ones I keep around here. I was told on airfoolers.com that this bike was raced in the 80s and was even featured in some of the old dirt wheels parts ads. ( I've yet to track one down so I have no proof) everything on this bike is set for tt racing (wide axle,extended swinger, works rear shock in lowest mount setting, roost factory air box, dg head, 38mm carb) it's def a top end motor

What gets me about this is that if I drive around at say half throttle it does fine and comes back down fine when letting off it and won't cause any issues.

It's only at the wot throttle where it does it every time consistently.
Sometimes the rpms are extremely high and will fall just a bit then repeat until it stops (370,380 jets)
Sometimes the rpms just stay extremely high and don't fluctuate. (Yesterday with he 390)
I only tested onetime with the 390 due to being pissed and tired of screwing with it.
The gentleman I bought this from I believe is a member here maybe captain wheezy (not positive) he said he never really rode it he got from a family friend who passed so I don't know much history on it. I have no idea what all is done inside engine honestly....it's about time to find out I guess!


As I side note I tried a test of my own and I turned the choke on and left it on while I rode it through the gears this morning it did NOT do the death rev thing after wide open throttle....of course it was running like it was flooded but the bike let the rpms fall back down instead of holding them at wide open.......I'm not sure if this helps or gives us any usable info just an idea.

knipfeldustin
05-18-2014, 10:16 AM
193725

Slide #

barnett468
05-18-2014, 10:18 AM
I was told on airfoolers.com that this bike was raced in the 80sif this is the case and it was raced in the pro class they were running race gas or they were getting their hieny beat.




I What gets me about this is that if I drive around at say half throttle it does fine and comes back down fine when letting off it and won't cause any issues. It's only at the wot throttle where it does it every time consistently.yes we got that.




As I side note I tried a test of my own and I turned the choke on and left it on while I rode it through the gears this morning it did NOT do the death rev thing after wide open throttle....of course it was running like it was flooded but the bike let the rpms fall back down instead of holding them at wide open.......I'm not sure if this helps or gives us any usable info just an idea.Ok, great thinkin. whish i would have thought of that.

It "suggests" [does not guarantee] that it is blazing lean. keep in mind, it burbles around 1/3rd throttle so it is RICH at that position not LEAN.

the extra gas might be enough to cool the cylinder below the point where it auto ignites the gas. the 10 plug will also reduce cyl temps but will not cause an excessively rich condition. hopefully you now see why i and others have been trying to reduce your cyl temps. the colder plug will do that, however, it might not do it enough. this is where timing and jetting etc.come in.


since you have no bigger main jet, I would try it with the fuel mix screw out one turn and then turn it in all the way. if it runs horrible or won't start with it in all the way, turn it out 1/2 way. one way makes it leaner all the way thru the throttle position and the other way makes it richer. at the very least i see a 400 - 410 main jet in your future sat the very least.

knipfeldustin
05-18-2014, 10:25 AM
I was wrong thought needle looked like it was all the way down but it is not I can move the clip up two more spots....sorry for the incorrect info


Needle says ... 6dpt Or 6dpl Hard to tell I'm leaning towards "t" as the last digit

193726


Here's something I noticed on the carb cap this morning the underside of cap appears to have a sealant applied but is dried and not sealing anything .....could it be pulling air through this cap gasket after slide is closed allowing it to continue running ?? Idk just a though193727

barnett468
05-18-2014, 10:30 AM
.
PS: Don't forget the gas level test with the clear plasic tube.

At the very least, it looks like their is a lite at the end of the tunnel.

http://4.bp.blogspot.com/-SvzOa_HxSKY/T68JQt1rUOI/AAAAAAAAA8A/CFbpFKze6SQ/s320/70s+Lite+Beer+004_x.jpg



OMG...its "light" as in "light bulb, NOT "lite" as in "lite beer" you tard!
http://www.freesmileys.org/smileys/smiley-laughing025.gif (http://www.freesmileys.org/smileys.php)

knipfeldustin
05-18-2014, 10:34 AM
As of now my plan is to test with the needle clip all the way down first.

Next ill try a different plug (prob tommorrow) .... U want me to go to a 7 or 10 ? I have seen both suggested here

I will then perform the air screw tests.

I will order some larger main jets this afternoon in the 400s range. Say 400, 410, 420 for starters ?

knipfeldustin
05-18-2014, 10:35 AM
I'll do the gas tube test today also

knipfeldustin
05-18-2014, 10:38 AM
On the race fuel subject....when i first got this bike and took it home I drained the tank and carb ....the smell of the whatever was in it was like nothing I've ever smelled before. I had a 310esr that ran on 110 so I'm familiar with what 110 smells like and whatever came out of is tank smelled like neither reg old pump gas or fresh race gas.......I've never smelled old race fuel though maybe that's what the funny smell was.....it was nothing like the turpentine smell of old gas ....def a first time smell for me and a friend both.

barnett468
05-18-2014, 11:14 AM
.
Howdy!

http://t0.gstatic.com/images?q=tbn:ANd9GcTDheK_NT7A9cIdJnV_1Pg7lGbLDWNu5 AVQnY60FToKElt_Wip72n1nHA



As of now my plan is to test with the needle clip all the way down first.That won't hurt, however, raising the needle will NOT increase the amount of fuel at WOT where your problem is. There is very specific reasons we suggest the things we do, and I even explained the purpose of doing this. Not ALL of us here are tards...well...not ALL of the time anyway. http://www.freesmileys.org/smileys/smiley-laughing013.gif (http://www.freesmileys.org/smileys.php)





Next ill try a different plug (prob tommorrow) .... U want me to go to a 7 or 10 ? I have seen both suggested hereI mentioned a 10 plug around 10 times now. I have not changed my mind. Unless the person suggestiong a 7 meant a 7 in a Champion [their number system is reversed] that person either doesn't like you very much or they are....well....possibly a tard.

I told you that a 10, which is just one heat range colder, will lower your cylinder temps by as much as 212 blazing degrees. Since your combustion chamber is already blazing hot enough to auto ignite the gas, if you think that making it even more blazing hot is a good idea then by all means feel free to do it. At least we'll finally get to see your combustion chamber along with what's left of your top end when you have to remove it because your piston vaporized into a plasma gas.





I will order some larger main jets this afternoon in the 400s range. Say 400, 410, 420 for starters ?As I mentioned several times, according to your description of how it runs on top end there is no indication that it is lean even with the 370. This is because you stated it less "dogginess" or was less "doggy" with the 370 then it did/was with the 390. Most peoples suggestions here are based upon your description of the problem. As I said, I'm not sure exactly how the word/term "dogginess" or "doggy" translates into a specific performance issue with your engine, but I do understand how it might relate to how the girl I dated last night looked after I sobered up enough this morning.


OMG...Hey BACON...either get some glasses or quit drinkin!
http://www.freesmileys.org/smileys/smiley-laughing025.gif (http://www.freesmileys.org/smileys.php)

DohcBikes
05-18-2014, 11:15 AM
All these words, one main jet change, and a short, pissed off ride.

You said its revving when you let off the throttle after a wide open run. What if the EGT is high enough, and the pilot is lean enough, that when it re-enters lean the pilot circuit, it takes off revving. Anybody got a theory on that? As some here know, im no scientist.

More changes, more ride reports please.

DohcBikes
05-18-2014, 11:28 AM
Theres so much conflicting info in this thread now that its really hard to follow.

Thats why tuning a bike is best done as a physical act.

Stop ruling things out by discussion, or you'll never find the issue. Get out there and TRY some stuff.

TUNING 101: If you change something, and it gets worse, do the opposite. If you change something and it gets better, even a tiny bit, do it more. The common theme here, CHANGE THINGS.

At this point my recommendation is to get a CR250F engine for it :twisted:

knipfeldustin
05-18-2014, 11:33 AM
No problem ill take it from here. Thanks everyone for the help up to this point.

barnett468
05-18-2014, 11:39 AM
On the race fuel subject....when i first got this bike and took it home I drained the tank and carb ....the smell of the whatever was in it was like nothing I've ever smelled before. I had a 310esr that ran on 110 so I'm familiar with what 110 smells like and whatever came out of is tank smelled like neither reg old pump gas or fresh race gas.......I've never smelled old race fuel though maybe that's what the funny smell was.....it was nothing like the turpentine smell of old gas ....def a first time smell for me and a friend both.Maybe it was the smell of race gas and pump gas mixed together.


Oh...My...GOD!
http://www.freesmileys.org/smileys/smiley-laughing025.gif (http://www.freesmileys.org/smileys.php)

:beer

DohcBikes
05-18-2014, 11:47 AM
LMFAO^^^^^Cmon Dustin you gotta see the humor in that one.........Right?

Just wanna hear some tuning results, then we can help. Your problem is a common one, but it happens for several reasons. If you make more changes, we will be more likely to be led in the direction of the culprit. Try to understand that it is very difficult to diagnose an engine over the internet. (even though the people on this thread are very good at it.)

Sincerely though good luck with the process, but dont rule ANYTHING OUT:beer

barnett468
05-18-2014, 11:50 AM
I will order some larger main jets this afternoon in the 400s range. Say 400, 410, 420 for starters ?Yes, I might start with the 420 at this point. If it fixes it but burbles at wot then go down 1 at a time until it's happy. Don't worry about the burble at lower rpm's, that can be fixed with a smaller jet needle or shorter jet needle choke height or different needle etc..

DohcBikes
05-18-2014, 11:55 AM
I might start with the 420 at this point.Yes absolutely.

I think in this case it WOULD be best to start with the 420.:D

El Camexican
05-18-2014, 11:59 AM
On the race fuel subject....when i first got this bike and took it home I drained the tank and carb ....the smell of the whatever was in it was like nothing I've ever smelled before. I had a 310esr that ran on 110 so I'm familiar with what 110 smells like and whatever came out of is tank smelled like neither reg old pump gas or fresh race gas.......I've never smelled old race fuel though maybe that's what the funny smell was.....it was nothing like the turpentine smell of old gas ....def a first time smell for me and a friend both.

Did you clean your petcock?

knipfeldustin
05-18-2014, 12:09 PM
Yes I will perform more tests and get back to you guys. Yes my petcock is clean.....and yes that was funny (mixed fuel joke) I'm not against you guys or trying to piss you all off. I am working on these tests but I do feel the need to comment back whenever someone asks me something I will meSs around with it today and see what happens.

barnett468
05-18-2014, 12:21 PM
.

Did you clean your petcock?
. . . http://t0.gstatic.com/images?q=tbn:ANd9GcTDheK_NT7A9cIdJnV_1Pg7lGbLDWNu5 AVQnY60FToKElt_Wip72n1nHA

I don't know who did it but someone cleaned the bejesus out of this one!


http://4.bp.blogspot.com/-RyCCzYOKtR4/UdwB0Gjn-xI/AAAAAAAAAno/iqZ_VszvHCM/s1600/featherless+iiii.jpg


Holy cr_p...it's a talking pig AND a naked chicken!
http://www.freesmileys.org/smileys/smiley-laughing025.gif (http://www.freesmileys.org/smileys.php)

barnett468
05-18-2014, 01:19 PM
Yes I will perform more tests and get back to you guys. Yes my petcock is clean.....and yes that was funny (mixed fuel joke) I'm not against you guys or trying to piss you all off. I am working on these tests but I do feel the need to comment back whenever someone asks me something I will meSs around with it today and see what happens.

http://t0.gstatic.com/images?q=tbn:ANd9GcTDheK_NT7A9cIdJnV_1Pg7lGbLDWNu5 AVQnY60FToKElt_Wip72n1nHA


Just some trivia. Imo, it is better to start with a super rich main on a bike that is new to you irregardless of how it runs. The reason is that it might have been jetted too lean by the previous owner and/or it might have been jetted properly but for warmer conditions and/or higher elevations and if you live near sea level and/or where it is much colder than where it might have come from etc.,it will be lean and might be lean enough to cause it to seize. This is the same if you have a new engine but performed high perf mods too it during the rebuild.


PLUG CHOP - You do NOT want to do this on any bike that you are unfamiliar with. The reason for this is, if it happens too be too lean, it might seize during the wot plug chop run. If this occurs, it would be unnecessary to do a plug reading. http://www.freesmileys.org/smileys/smiley-laughing013.gif (http://www.freesmileys.org/smileys.php)

This actually happened to someone on the site around 6 months ago. I asked him why he did that and he said a mechanic told him to. :rolleyes:



It must have been a HONDA mechanic! Ahhhh, ha ha...
http://www.freesmileys.org/smileys/smiley-laughing025.gif (http://www.freesmileys.org/smileys.php)

El Camexican
05-18-2014, 03:10 PM
.

. . . http://t0.gstatic.com/images?q=tbn:ANd9GcTDheK_NT7A9cIdJnV_1Pg7lGbLDWNu5 AVQnY60FToKElt_Wip72n1nHA

I don't know who did it but someone cleaned the bejesus out of this one!
Keep in mind it's spelt "petcock" and not "pet cock" which as we all know operate best if polished regularly

El Camexican
05-18-2014, 03:14 PM
I know this is as half assed a way to determine a main jet as there is, but I’ll throw it out there anyway. I believe the 250 Tri Z came with a similar Mikuni carb and a 470, or 480 main. It that’s true I would think you would want to start with at least a 450 main on your Honda and if need be work your way down.

barnett468
05-18-2014, 03:34 PM
Keep in mind it's spelt "petcock" and not "pet cock" which as we all know operate best if polished regularly

http://t0.gstatic.com/images?q=tbn:ANd9GcTDheK_NT7A9cIdJnV_1Pg7lGbLDWNu5 AVQnY60FToKElt_Wip72n1nHA

Hey...give me a break...isn't it enough that I'm a pig that talks and now you want me to read well too. Why don't you just BITE MY BACON!.


Holy crap...pig..bacon....polish..pet...
http://www.freesmileys.org/smileys/smiley-laughing025.gif (http://www.freesmileys.org/smileys.php)

barnett468
05-18-2014, 03:41 PM
I know this is as half assed a way to determine a main jet as there is, but I’ll throw it out there anyway. I believe the 250 Tri Z came with a similar Mikuni carb and a 470, or 480 main. It that’s true I would think you would want to start with at least a 450 main on your Honda and if need be work your way down.

http://t3.gstatic.com/images?q=tbn:ANd9GcQxr9P5OYMQvRhaWZ5QfBVTS7isj4zCS JQ6Ku1TmxO1HY-ScDvHod7NuYM

Hey...that's not as half assed as the way we've been doin things!


Holy cr_p!
http://www.freesmileys.org/smileys/smiley-laughing025.gif (http://www.freesmileys.org/smileys.php)

DohcBikes
05-18-2014, 03:45 PM
I know this is as half assed a way to determine a main jet as there is, but I’ll throw it out there anyway. I believe the 250 Tri Z came with a similar Mikuni carb and a 470, or 480 main. It that’s true I would think you would want to start with at least a 450 main on your Honda and if need be work your way down.There we go.

Only thing i would add is why not a 480 first but anything up in this range is gonna at least give an indication. As barnett mentioned, I like to start way rich and lean it out till its happy.

Again, we're very focused on the main jet here, but dont overlook some pilot jet tuning! Process of elimination at the very least.

knipfeldustin
08-16-2014, 05:55 PM
It's been awhile but the death rev has finally been fixed!! I tried so many different things and tore into the top and bottom ends, new gaskets, different fuel octanes, carb settings and little hondabond along the way. All of this was to no avail. We even had this thing continue running for a few seconds after pulling the plug wire off (explain that?) but anyways finally borrowed a different carb and thumb throttle setup from a friend of mine and its running like a champ, no death rev, very responsive and pretty damn fast. I still have no clue as to how this was caused by my old carb or why but its fixed now and I'm happy.... Learned along the way it has pretty aggressive porting and has a .060 over bore (piston says 1.5mm 431p6 cd) appears to be a fairly fresh top end. Crank seals ended up being good when I checked them also. I should have just tried a different carb a long time ago but never thought it would be that easy. Just thought I'd share with you guys what all i found out and I appreciate the help along the way.

nicker71
08-17-2014, 12:56 PM
I've said it was probably that old POS mikuni carb that was on it. And I was right!!