1984 atc250r too much smoke

[Islandbiker5000]

Hi everyone. My names chris and im new to this site. Im here in oregon ridin the dunes. Ive always had trikes but in 4stroke. I just recently bought a 250r honda and i have no idea about them. I have an issue i was hoping someone can help me. This trike seams to somewhat bog when i nail the t throttle. It smokes way more than other 2strokes. Everything is factory on it no mods. I have done: cleaned the carb. New oem airfilter.new plug. Factory airscrew setting. 32:1 synthetic mix. It smokes alot. When i get on it hard it really smokes alot and is sluggish. Sometime it will hit the powerband hard but only sometimes. Has anyone ran into this problem. I really want to ride this this summer.

[RIDE-RED 250r]

Welcome aboard! :)

Sounds like the first thing you need to do is look into dialing in your jetting.

If you aren't sure how to go about dialing in your jetting, this thread should get you well on your way to BRAAAAPIN good and proper! http://www.3wheelerworld.com/showthread.php/55086-Carb-Jetting-101-Terms-Tips-and-Jetting-Theory

[Islandbiker5000]

Ok i will start there. Thanks for the link i really apreciate that. Do you think do to that due to age the stock jets arent any good anymore?

[barnett468]

Ok i will start there. Thanks for the link i really apreciate that. Do you think do to that due to age the stock jets arent any good anymore?


Helllo


Jets do not wear out.

1. Do a compression test and tell us what it is. Around 160.0 is good, less than around 140 MAY be new ring or bore time etc.

2. What color is the smoke ie, white/lite gray is oil, very dark gray/black is excessive fuel.

3. Does it “burble/sputter” on acceleration [too rich]or does it simply not “go” [flat spot].

[RIDE-RED 250r]

No, jets really don't "wear out". They can just get fouled to the point you can't get them adequately clean by conventional do-it-yourself methods.

Most things like wheelers, sleds and whatnot that came with 2-stroke engines were jetted from the factory a little on the rich side for the most part. There are a few reasons for that.

If you engine has richer than OEM jets installed, it's likely the reason is due to at some point in it's 30 years some modifications were made to it. It's really hard to say though.

Do a quick compression test on it to make sure compression is up to par. I am not sure what numbers the Air-Hammers should be at. I'm sure if you search that topic plenty of results will pop up.

If that checks out, then proceed with your jetting adjustments.

One of 2 things will happen, you will either get it dialed in and running the way it should. Or you will have trouble dialing it in and chasing your tail round in circles. If the second scenario is the case you have other possible issues and we can help you through that a step at a time.

But for now, check compression and jetting and get back to us..

[Islandbiker5000]

It somewhat sputters when i nail the throttle then it takes a second and then the powerband hits kinda. The smoke is white. It just doesnt feel like its as fast as it should be

[RIDE-RED 250r]

Sounds like it is too rich by the way you describe it..

Does the sputtering occur below 1/4 throttle or 1/4 and higher?

If it occurs below 1/4 throttle then your pilot jet is the one you want to be looking at to dial in better.

If over 1/4 throttle, then the main jet and possibly slide needle position is what you need to look at.

[Islandbiker5000]

Ok ill do a compression test and mess with the jetting. The plug is black and sooty also. Ill try it and ill let you know. Really thanx for the help i really apreciate it

[RIDE-RED 250r]

No problem.

Post a good pic of your sparkplug.

Black and sooty is a classic sign it's too rich.

[barnett468]

Ok ill do a compression test and mess with the jetting. The plug is black and sooty also. Ill try it and ill let you know. Really thanx for the help i really apreciate it


Hello


Thanks for answering my questions so quickly and in good detail.


The following are my suggestions only, others will have different ones.

You may have 2 problems as I described. The compression numbers I asked for will help a little, unfortunately compression gauges often vary from gauge to gauge by up to 15 psi so the numbers will just be a general guide.

The "white" smoke you describe is oil as I mentioned, your rings may be worn causing low compression, low comp can cause an otherwise properly jetted bike to run rich and/or have low power feel and burble upon acceleration.

The "burble" is typically rich however a carbon fouled or otherwise loaded up plug etc can occasionally cause a similar feel.

Install new plug, try again, check color after 30 min riding, if burble still exists reduce main jet by 2 sizes and try again. Check plug color again, lite tan is good, dark tan is slightly rich, DRY dark black is too rich, any moisture on any color plug is oil.


Hope this info helps

[barnett468]

Hello


If you find your jets to be plugged slightly [which is unlikely since your bike sounds rich] and you can't get them clean you can simply take a "number" drill of similar size to the jet and spin the jet around on it with slight force. Done this many, many times works great and dies not damage the jet whatsoever.

If you get the number off the sides of your existing jets that Ride RED was referring to then please post them as this info may help.

[Islandbiker5000]

My pilot is 50 and main is 130.

[barnett468]

My pilot is 50 and main is 130.


Hello

Thanks for the info. T factory main is 158 there is nno mention of the pilot jet size but 50 is close enough for now. Are you absolutely 100% positive you main says 130 not 150 or something.


1. What is your elevation?

2. If your main is 130 then your bike is majorly LEAN, this is a major part of your "bog" problem, please install a 155 for now.

3. Your excessive white smoke means your motor is burning oil which means your compression should be low. Low compression will also cause a bit of a "bog" condition. No compression, no power!


Let us know

[barnett468]

CORRECTION - Your oil smoke may be caused by a bad right crank seal sucking oil from crank case however it will typically [but not always] idle high due to an air leak if this seal is bad. You may need to have a crank case leak test done.

Exactly what type of 2 stroke oil are you using?

[barnett468]

Stock jetting on the 83-84 250r.is 130 on the main 50 on main.



Hello Islandbiker and ATC 300R


That's not good to hear, why is the Honda manual different?


81-84 ATC 250R OFFICIAL HONDA MANUAL JETTING PG 3-1 MAIN 158 AIR SCREW 1 3/8

http://www.oscarmayer.net/atc/manuals/honda/atc250r_81-84_servicemanual.pdf



85-86 ATC 2506 OFFICIAL HOMDA MANUAL JETTING PG 3-15 MAIN 142 AIR SCREW 2

http://www.oscarmayer.net/atc/manuals/honda/atc250r_85-86_servicemanual.pdf

[RIDE-RED 250r]

Admittedly, I do not know off the top of my head what stock jetting is for the '83-'84 R's.

I do know the 81-82's run a smaller carb than the '85-'86's. Not 100% positive, but pretty sure the 83-84's do as well...

I'm having trouble loading the manual links posted, and of course at this point we don't know for sure what carb is on the trike in question..

But, it seems little odd that an engine running a bit smaller carb would be jetted that much fatter on the main than larger carb found on the water pumpers.

Not contesting the info you posted, just an observation.

You raise a good point about the clutch side crank seal too. Along with the excessive smoke, it's going to stink like crazy too. Not the kind of sweet smell of 2-stroke oil.

Would like to see some compression numbers on this..

[Islandbiker5000]

I thought maybe a crank seal it doesnt idle high tho. I can control idle very easily. My jets are the stock numbers. I got the information from freds honda. I cant tell if the oil is low because i just see a cap and no dipstick? Whats with that

[RIDE-RED 250r]

That is for transmission oil only. There should be a level plug somewhere on the clutch cover. Basically, just pull the level plug and if oil seeps out you are good to go. If not, ad oil through the fill hole till oil seeps out the level hole.

If you find that the engine is consuming transmission oil and not leaking it anywhere, that's a tell-tale sign of a bad clutch side crank seal as well.

[Islandbiker5000]

Yeah i see the threaded plug on the clutch side it doesnt have a stick. I rotated the crank and can see the clutch covered in oil but its not overflowing? I thought they only take a half quart of oil?

[RIDE-RED 250r]

You are correct, they take less than 1 qt. I don't know exactly what the models like yours take. I'm sure 300r can shed light on that.

Just check the oil level with the level plug on the side.

[Islandbiker5000]

If its a bad clutch side crank seal is that hard to fix? Or should i have someone do it at a shop? Ill have to pull the motor cuz no one works on trikes over here

[Islandbiker5000]

Ok i found the little plug. Its kinda rusty so im going to soak it with pb blaster and will check it in a few minutes

[yaegerb]

A couple tests I would do to make sure you are good to go. First, a compression test to see if the rings are still good. The correct compression is 156psi +/- 14psi.

The next test you need to perform is a two stroke pressure test. Below is a link to how to properly perform a pressure test and you can also purchase the three way valve from Harry Klemm himself. Harry is building mine right now and its a helluva lot cheaper than the motion pro tester. The motion pro tester is below the klemmvintage link.

http://klemmvintage.com/airleaks.htm

http://www.ebay.com/itm/Motion-Pro-2-Stroke-Leak-Down-Tester-Tool-08-0071-/151016571400?pt=Motors_Automotive_Tools&hash=item23294a0208&vxp=mtr

[barnett468]

Hello


Hope no one misunderstands this post. I have no intention of ruffling any feathers or contradicting anyone regarding their claims of what the stock jetting of an 81 thru 84 ATC 250R should be. Since this post can be read by anyone who pulls it up in the search engine I personally think this info is important so they do have the correct jet setting to start with as a baseline for their bike. I am also curious myself to find out the reason for the discrepancy in the info. It is possibly that the info supplied in the OEM Honda manual is an error but it would need to be disproved through documentation if possible to render it so.

The previous info I posted is direct from Honda not me. It comes from a 1983 version. If anyone cares to dispute the accuracy of Honda’s information please call them directly at 310-783-2000 it has nothing to do with me. If anyone has PROOF that there is a jet setting in another official OEM Honda service manual, OEM Honda service bulletin or OEM Honda parts manual please post it and the print date/year of that manual etc.

There are other online and paper sources [Clymer manuals etc]that supply jet info however that info is subject to accuracy and/or interpretation including the info Islander received from “Fred’s” Honda shop. They did not give you this info directly from the OEM manual I POSTED. The likely hood of them having an OEM Honda Parts manual is virtually non existent therefore the accuracy of their info is questionable.

If one had purchased a NEW bike in 84 that the dealer had not already rejetted because it ran to bad to sell or purchased an NOS Caburetor in a FACTORY SEALED BOX then this info however well intentioned is also questionable.

After working at Kawi R and D and being a parts manager at a large Honda Kawi store I have seen a lot of unusual things. Based upon this I personally believe the Honda manual only no matter how strange the jetting might seem to be.

xxxxx

Stock jetting on the 83-84 250r.is 130 on the main 50 on pilot. I have two stock 83-84 250r carbs.They are 30 mill Keihins.both have stock jetting 50 130.

Please see intro comments.

xxxxx

But, it seems little odd that an engine running a bit smaller carb would be jetted that much fatter on the main than larger carb found on the water pumpers.

Yes I understand and agree on the surface it certainly does seem strange but t this can be due to many mechanical variables. Please see intro comments.

xxxxx

I have two stock 83-84 250r carbs.They are 30 mill Keihins.both have stock jetting 50 130.

Please see intro comments.

xxxxx

My stock 85 250r carb is round slide Keihin 34 mill.with 140 main jet.

The official Honda manual I posted for 85/86 says 142 is stock, the 140 is or elevations between 33000-6600 ft and temps between 22 and 104 deg F. or 5000 ft and above and temps between 0 and 22 deg F. This jet setting is done at the discretion of the customer NOT by Honda.

FROM PG 3-2 OEM 84/85 ATC 250R MANUAL

85 CARB # PE37A 142 MAIN 142, PILOT 52, 86 CARB #PJOSA MAIN 145, PILOT 42.

xxxxx

My manuel also says the jets I listed are stock .

Please post photo or give exact mfg of manual and if it is an OEM HONDA manual please supply the print date/year on bottom of front page.

xxxxx

I thought maybe a crank seal it doesnt idle high tho. I can control idle very easily.

It will almost always have a high and/or erratic idle if this is the problem but check it anyway.

Xxxxx

My jets are the stock numbers. I got the information from freds honda.

Not necessarily, please see intro comments.

xxxxx

If its a bad clutch side crank seal is that hard to fix? Or should i have someone do it at a shop? Ill have to pull the motor cuz no one works on trikes over here

If you have the tools you can probably do it yourself after watching video if you are mechanically inclined.

Are you saying they will work on the motor but will not allow a 3 wheeler into their shop?

xxxxx

One way to check the flywheel side seal is to pull the flywheel cover off and see if it smells like gas.

It will almost always have a high and/or erratic idle if this is the problem but check it anyway.

xxxxx

Below is a link to how to properly perform a pressure test and you can also purchase the three way valve from Harry Klemm himself. Harry is building mine right now and its a helluva lot cheaper than the motion pro tester. The motion pro tester is below the klemmvintage link.

You can also use a cheap radiator pressure tester


Xxxxx



Hope this and others info helps.

[barnett468]

Hello Islander


I personally would not ride or re-jet the bike until you do your compression test and crank vacuum test as recommended and determine the cause of your excessive smoke. In my opinion there is no point to it. Doing so could damage it further. I know it's a pain.

[barnett468]

Hello

Even if the OEM manual is incorrect installing a main jet that is larger than the OEM setting will do no harm providing it is temporary. It will simply load up the plug and run badly if it is too rich, however installing a main jet that is substantially smaller than the OEM setting can quite possibly do damage to your motor if it is left in for even a brief time. I personally think it is better to be safe than sorry and would simply start rich and go leaner as necessary instead of the opposite when there is any questions as to what an OEM jet setting is but that's just my opinion.

[barnett468]

Hello Islander


I forgot to mention Honda says that 158 main jet is for all 81 thru 84 atc 250r's and the carb number for all those models is PE23A. Look on the side of your carb and post all the numbers and letters you see any where on it.


On the inside of the forst oge of the m81-84 manual i mentioned above it says "issiue date August 81'", on all the other pages it says "issue date May 81'". This means this is a factory re-issue of the the original 1981 manual with no revisions, so in 81 they apparantly planned no jetting changes all the way thru 84 and because there are no revisions this is exactly what they claim they did. Interesting. So anyway like I mentioneed, if anyone has a factory manual different than this one with a different jet setting please post the info.


Thanks

[bkm]

A couple tests I would do to make sure you are good to go. First, a compression test to see if the rings are still good. The correct compression is 156psi +/- 14psi.

The next test you need to perform is a two stroke pressure test. Below is a link to how to properly perform a pressure test and you can also purchase the three way valve from Harry Klemm himself. Harry is building mine right now and its a helluva lot cheaper than the motion pro tester. The motion pro tester is below the klemmvintage link.

http://klemmvintage.com/airleaks.htm

http://www.ebay.com/itm/Motion-Pro-2-Stroke-Leak-Down-Tester-Tool-08-0071-/151016571400?pt=Motors_Automotive_Tools&hash=item23294a0208&vxp=mtrYeager is spot on. On an older machine, any machine, the internal condition of the engine must be evaluated before any tuning can be performed. You're pretty much pissing in the wind until you have verified the condition of the engine. Then you need to evaluate the carb condition. A worn out carb, even if clean, is still a worn out carb.

This is just my .02, but if funds allow it, ditch the stock carb and buy a newer, better replacement. You will thank yourself in the long run.

[Islandbiker5000]

Hi all. All your info has been simply badass and i really apreciate it you have no idea. I just did a compression test and the result was 132 psi. Should i replace the rings? And or piston?

[yaegerb]

Hi all. All your info has been simply badass and i really apreciate it you have no idea. I just did a compression test and the result was 132 psi. Should i replace the rings? And or piston?

Yes, I would replace the rings and step up one size on the piston and bore the cylinder, unless you find that all you need is a hone job. A reputable machine shop will be able to tell you if you need a bore vs. a hone....or take pictures and post them up here for us to look at and evaluate.

Also, before you go ripping into the top end, I still recommend a pressure test so you can see if any of your seals or gaskets need replacing. Its highly recommended to do this prior to any other work, that way you can build it 1 time instead of taking it all apart and THEN doing the pressure test, only to find that you have to do it again.

[Islandbiker5000]

Ok cool thanx man. I will have to put together my coolant tester to fit on the sparkplug hole to add pressure. Ill let you know what happens. Ill do it here inna few minutes

[yaegerb]

Ok cool thanx man. I will have to put together my coolant tester to fit on the sparkplug hole to add pressure. Ill let you know what happens. Ill do it here inna few minutes

Did you check out the link I posted earlier? You don't perform a 2 stroke pressure test from the sparkplug hole. You pressurize the engine from the intake side and you plug the exhaust side. I would suggest reading the link I sent, its very detailed and tells you everything you need to know. You will have to make a T fitting with a pressure gauge to properly test the motor. You pressurize the motor with 6 PSI and the engine must hold that pressure for 6 minutes with NO decrease in pressure. Also note that the motor has to be at the bottom of the compression stroke or BDC.

Below is a fairly decent video on how its done. I will note that I don't agree with his pressure methodology. I use the 6 psi for 6 minutes rule.

http://www.youtube.com/watch?v=Ii5K0vbOoSE

[RIDE-RED 250r]

Yes, I would replace the rings and step up one size on the piston and bore the cylinder, unless you find that all you need is a hone job. A reputable machine shop will be able to tell you if you need a bore vs. a hone....or take pictures and post them up here for us to look at and evaluate.

Also, before you go ripping into the top end, I still recommend a pressure test so you can see if any of your seals or gaskets need replacing. Its highly recommended to do this prior to any other work, that way you can build it 1 time instead of taking it all apart and THEN doing the pressure test, only to find that you have to do it again.

Ya know... It's not a heck of alot more money for a set of new crank bearings and the complete engine gasket set vs just a top end set. If it were me, I would freshen up the crank bearings and seals too.....

But it can seem a daunting task to someone who hasn't done it yet...

[barnett468]

Xlnt, job on the pressure test. I personally would fix it as necessary.

As Ride Red 250R suggested I would also consider replacing bearings etc since you are already ”there”. “Do it once, do it right.”

As mentioned a few times above, you need to do this test PRIOR to removing top end etc. We must know if your seals are leaking and therefore the cause of your “smoking” problem.


PRESSURE GAUGE CONNECTING LOCATION - It is irrelevant whether the gauge is hooked up to the intake or the spark plug hole. See excerpt below from Harry’s article posted by Yeagerb. The factory race mechanics do it either way. The results are exactly the same.

The Pressure Test

The step by step is :

A) Seal off the intake manifold with a plug or rubber gasket

B) Seal off the exhaust port with an automotive expanding rubber “freeze plug”.

C) Attach an air fitting that lets you pressurize the motor (usually thru the inlet plug or the spark plug hole

D) Pressurize the motor to 6-9 psi via a hose that has an in-line gauge.

E) Watch your in-line gauge for 5-10 minutes to confirm you have “absolutely no loss” of air pressure. A loss of even 2-3 psi is not acceptable.

F) If your gauge shows a leak, spray the gasket seams and seals on the pressurized motor with WD-40. The WD40 will make visible bubbles, and a leaking sound, when you spray the leak point.


PISTON POSITION FOR TEST – The piston position is irrelevant, however it is typically done with it in the bdc position. The air pressure from the pump will blow by your worn rings and factory ring end gap as though they weren’t even there.

LEAK LOCATIONS - You may notice a leak at the ex flange or base gskt etc. Providing they are not excessive and your pressure does not drop faster than around 2 psi per min you will still easily be able to determine if your bike has a SIGNIFICANT leak at the seals. If your seals leak they should be replaced. If they don’t leak but you DO have other leaks these should be fixed and the seals should then be rechecked via test. You can temporarily seal these leaks for the purpose of the test by using black rtv silicone on them.

I prefer a 0 leak motor however as Harry says you can run a motor under low stress conditions with a mild leak and never have a problem.

TEST PRESSURE - I and everyone else I know use 8-9 lbs not 6.

TEST LIQUID - Harry uses WD40, most people use soapy water. Mix about ½ to 1 tablespoon of dish soap per pint of WARM water. The warm water helps it mix easier without the need for shaking it.


XLNT YOU TUBE PRESSURE TEST VIDEO

http://www.youtube.com/watch?v=zdq7NRcUIp8

[barnett468]

Hello Islander


Forgot to mention the following

PRESSURE TESTER – As I previously mentioned a radiator tester will work perfectly [see video] since you have one your there! You can also use an inexpensive “mighty vac”. They are reversible so you can apply vacuum or pressure. You can get the tapered or expandable rubber plugs at industrial hardware stores. The tapered ones tend to “pop” out.

[Islandbiker5000]

My compression tester was broken. I bought a new one and my reading was 152psi

[yaegerb]

Cool, that's a good reading and rings should be solid.

[Islandbiker5000]

Can i still pressure test the motor even tho i have 152 psi compression?

[yaegerb]

Can i still pressure test the motor even tho i have 152 psi compression?

I would pressure test to ensure the seals/gaskets are still in good working order.

[barnett468]

Can i still pressure test the motor even tho i have 152 psi compression?

Hello Islander

Yes absolutely, your cranking compression has very little to do with your seals leaking etc. You absolutely need to do this test. You need to know if your seals/gaskets leak etc and why it smokes and hopefully where your trans oil went. Unless someone poured oil into your muffler your right seal is bad which sucked the oil out of your gearbox. That's how that works.

What gas mix OIL are you using EXACTLY?

[barnett468]

Hello Islander


Since it looks like the true stock jetting question will be extremely difficult to document from Honda and therefore will remain an unsolved mystery I personally can suggest 2 things, 1. Make a post asking what jet size they run in their box stock 83-84 250r if in fact there is such a thing and use the highest number as a starting point or simply be safe and once your problem is resolved start with a slightly larger main then your current 130 like a 145 since it was probably running with the 130 before.

Thanks to all those that put effort into researching this and for patiently putting up with my OCD, lol. If I wasn’t a bit OCD though, the 86’ Tecate along with a few other Kawi products would have been a pile for sure so I guess it’s not all bad [at least to Kawi owners anyway].


The 81’-84’ manual printed Aug 83’ says 81’ thru 84’ carbs are #PE23A with 27 mm bore.

The sales brochures say the 83’ and 84’ have a 30mm carb but list no carb #.

This means the 81-84 manual is correct for 81-82 but not for 83-84.

The Clymers manual says 81-82 used a 155 main, since this does NOT match the OEN Honda manual clymer’s is incorrect. Since they are clearly wrong about the 81-82 jetting it is reasonable to question the accuracy of their 83-84 jetting info. Clymers is saying Honda used a 155 main on a 27 mm carb and a 130 main on a 30 mm carb.

On Ebay I located an original 81-82 manual and the 81-84 manual I posted. Because they reprinted the 81-82 manual late in 83 it looks like they may never have made an 83 or 84 specific manual. Since the carbs are clearly different between 81/82 and 83/84 and other parts are obviously different they may simply had the shops use the 81-82 manual for all and snt an additional 82-82 service manual supplement. I worked at a Honda dealer before and thus is exactly what the occasionally did. This means that if this is the case, unless someone has one of those mini manuals etc we will never know what Hondas jet specs actually were for 83-84.

CLYMERS MANUAL – I would guess they get their info from a printed Honda manual however since their jetting for the 81-82 manual clearly contradicts the OEM Honda manual where did they get their info because they didn’t get it in the manuals I mentioned. Is the 155 jet size just a typo by someone with astigmatism, could be?

The other strange thing is, it takes fuel to make hp so in motors of the same bore/stroke ex and carb etc the motor that required a larger main jet is obviously the one that will make the most power. The difference in motors would then be due to different port timings and/or compressions much like changing the cam size and/or compression chamber size in your cars engine but nothing else. Sooo.. if in fact the 82-84 does actually use a 130 main then why? Did they reduce the hp in those two years or is it due to carb design being more efficient much like the difference between a std carb and a fuel injected carb etc?

In researching the cylinders and pipes all I found was different cyl numbers from 81-82 and 82-83/84 and the 81/82 to 83/94 pipes and mufflers. This could be due to several things however so this info is useless, lol.

Since it looks like the true stock jetting question will be extremely difficult to document from Honda and therefore will remain an unsolved mystery, I personally can suggest 2 things, 1. Make a post asking what jet size they run in their box stock 83-84 250r if in fact there is such a thing and use the highest number as a starting point or simply be safe and once your oil smoking problem is resolved, start with a slightly larger main then your current 130, like maybe a 145 since it was probably running ok with the 130 before.

[barnett468]

Hello Islander and all others

I have come to the mountain and seen the Holy Grail, lol. Someone has been fortunate enough to have access to an 83 OEM Honda addendum to the 81-82 manual and showed it to me and the 83 and I assume the 84 ATC 250R did in fact come with a 130 Main stock.


How are your pressure test plans going, any results yet?

[barnett468]

Hello


just looked again and apparently the manual I previously looked in online did not fully download on my computer before I looked at it. The addendum I thought existed is at the very end of the manual.


Pg 18-12 comes before pg 18-3 and has jetting listed under the air box section, pg 18-3 is listed AFTER pg 18-12 and has all other carb info but no jetting info. Nice.