Need some engine Diagnosis pointers.... Experts Help!

[Darius1502]

Ok...

My Tri Z does not start. Here is what I know:

1) I will start if I pull-start it.

2) It runs rough in the low end...but clean in the mid and top

3) It will continue to run and won't stall as long as I give it gas

4) Sometimes it will idle but sometimes it will stall if I try to get it to idle.

5) It smokes alot

I checked the float bowl, I did tinker with the pilot jet and the idle screw. I have not found the correct setting because the engine is running so rough.

I did put in a new base gasket. I am thinking it may one of the reeds.

The trike was running fine until I put Blue Marble in it. I don't think the Blue Marble caused this but I think it can coincidentally made all this come about.

I also have not had time to really run through a couple of tanks of gas. I hear that this is required when using blue marble.

I did switch back to Bel Ray and the Z still exhibited the same behavior.

Thanks guys!!

[70binder]

2-stroke? make sure you didn't mix it too rich on the oil, that'll make nice smoke and soften the topend out, i dont know if you have that. same thing with too much fuel. try turning any mixture needles for the lowend in 1/4 a turn at a time in (Holley says 1/4 turn on theirs, so i'm just saying, you may have a sensitive needle, 1/8 of a turn may work also) rough lowend usually is too much fuel, if it was excess oil, it would run rough like the choke is on in the topend. Your timing may have retarded, makes for one heck of a bish to start but runs fine when revved up (you don't have timing advance i assume) i'd say, if it were my tri-z, take your lowend needle in 1/2 a turn to rough it in, try starting it, let it run for a minute to make sure the fuel system has had time to adjust to the new setting. if better, try turning it in again, and repeat the run for min/tune carb process until you lean out too much. Hope this helps, as this is what i used to do with my old nitro car after a new pipe, and then after i ported for 60% more power, it gave too much fuel then. Maybe thats your prob?

[4cylinders]

hey, before you do to much, do a compression test, first dry, then wet- ashot of fuel in the cylinder. post your results for more info.

[bigredhead]

What would a broken or damaged Ring do ?

[70binder]

this is what a broken ring does.

http://img.photobucket.com/albums/v303/c0mpl3x/Image084.jpg
ring shashed horribly, there is 2 layers of one ring there

http://img.photobucket.com/albums/v303/c0mpl3x/8579cf0b.jpg
when the ring decides it's gonna breakdance

http://img.photobucket.com/albums/v303/c0mpl3x/fbed2d56.jpg
and what happens when mr. ring meets mrs. valve, they have little rings and valve shavings

[03 ORANGE SHEE]

im just wondering if your cdi,coil, or stator is getting ready to take a crap, mine did the same thing a month ago, damn coil, i run a 98 600 grizzly coil now, much hotter spark than a stock z coil and for $38 new!

[TimSr]

Difficult starting, rough idling, but clean once you start to open the throttle up sounds like a clogged pilot jet to me. I would remove the pilot jet, and also remove the air screw. Then blow some carb cleaner with that red straw through the hole the pilot jet came out of, and make sure it exits. Then, of course make sure the pilot jet is clear before putting it back in. All it takes is one grain of sand to give you endless headaches, and the pilot clogs very easily. Its a much tinier orifice than a main.

[Derrick Adams]

I'm actually having this exact same issue with my Z right now! Last time I went to ride it, it wouldn't start. It ended up having so weak of spark that you couldn't even see it, just hear it. Then I went out the other day to work on it, and it had great spark..?WTF!
Anyhow, I had previously swapped on a 39mm keihin and am trying to get it to idle. This thing refuses to idle! I changed the choke and have been dropping the pilot jet. Right now I have a 048 pilot jet in it (stock is 055)with the needle all the way down and the idle screw almost all the way in to get it to idle! Still spewing bellows of smoke, like it's rich.
(Another issue) My bike also wouldn't start unless I kicked it 20 times. Turns out my reeds were bad. Changed those today and it started 2nd kick! Still don't idle but it starts.
So, time to start a post on symptoms of coils going out!

[Darius1502]

Well....godang...I am sick of this thing. I checked the reeds...perfect. I checked blew air and carb cleaner into the pilot jet hole and the air screw hole. In fact all the jets.

I give up...time to go to the gym. I would rather spend time on myself then this rattle trap!

Until next week!

[Dammit!]

I bet your R will start. :D

[wolfspider]

try a new plug if you haven`t already, its so cheap its worth a shot!!!!!

[Derrick Adams]

Dammit, do you ever have anything constructive to say?

Darius, What's the deal? You've been working on your bike for over a month and have gotten nowhere. Time to take it to a professional! Seriously, if you keep tinkering with it, and not fixing it, your just going to get pissed off at it and never enjoy the bike. It seems you don't know exactly what your doing when it comes to carbs(please don't take offense to that) Find someone who does. You have a very nice trike and when you get on the board and talk down about it, that's just not right.

If your local dealer won't work on it, go to the next town and check there. Sooner or later, someone will take a look at it. And when you do get it all sorted out, Don't store it setting up on the grab bar!

[Curtis-Tecate3]

I have the same opinion as Tim on this one. Clogged pilot jet. I would completely disassemble the carb and make sure you don't have any junk in the float bowl. Remove all jets and make sure you clean them well and can see "daylight" through them particularly the little pilot jet. Don't just give everyting a squirt of carb cleaner and think that you are done. You need to thoroughly clean that carb.

Curtis.

[Dammit!]

Dammit, do you ever have anything constructive to say?



I think he knows I'm just messing with him. It's an R thing. ;)

[Darius1502]

Dude the R starts on the first kick...just like my Z did before BM...ha ha!!

Its ok....I love that Z and I am just giving it a hard time...since well its giving me a hard time.

I may take the trike to a shop. I appreciate the help that everyone has given me here.

Its pretty strange that the Z just started acting up. I need to take some time and pull start her and then run her for a while. It will start like that. I still think there is crud somewhere that needs to be burned off.

I'll let everyone know...if it does not start in 1 week though...I am parting it out on ebay...

Just kidding!! :naughty:

[Mr. Sandman]

Darius, Something else to check would be your air filter. Why? Because I noticed you store your bikes in the upright position. If you stand them up without draining the float bowl first, all the gas/oil mixture in the bowl will run into the air box and the filter will soak it up. The gas will eventually evaporate, but the oil will remain in the filter and even a clean air filter that is oversaturated with oil will cause a bike to run like crap.

[Darius1502]

Thanks for the advice Mr. Sandman, I did do the following:

- cleaned the air filter (a K&N) and re-installed it.

- even tried starting it without the filter on (just for a sec.) but it did nothing

Derrick: No offense taken..thanks for the help. I wish you lived in Texas brother!!

- I checked spark...I have a several visible blue sparkes coming from the plug

- I took out the pillot jet, choke assembly, main jet, needle jet, checked the float levels and cleaned all of them, blew air in them. The carb is spotless

- put in a brand new plug (I have 5 of them now)

At this point its hard for me to figure out. I still think that the Blue Marble did something that needs to be burned off. We will see this weekend!

I have not done a compression check since i don't have the tools. I did re-install the top end before this all started happening and I put in a new base gasket.

I did re-use the top end gasket. When it was running I had no leaks and the compression is enough that it hurts my foot to kick her.

- I even took off the cylinder dome and cleaned all the carbon from the piston and dome.

Still it seems like a carb issue...but what??? Should I let the thing soak in varsol for 1 week?

Believe me those jets are spotless...again lets see what happens when I pull start her and get it running. When I do that, I'll keep her running for awhile and see if maybe the Blue Marble will equalize and burn all this crap off (assuming there is crap to burn).

Thanks!!

Thanks for taking the time to help!!

[Sqirtster]

I was a Honda/Kawasaki Tech at Honda of Florence in Florence KY, so I'm not real big on Yamaha information. Does it have a variable intake or exhuast valve in the cylinder? The K.I.P.S. (Kawasaki Induction Powervalve System) used two rotating valves in the cylinder to raise and lower the exhaust port with engine RPM. It was VERY common to find these carboned up from not being run very hard. If it was stuck in the "Top" position, it ran great on the top end and "4-stroked" on the bottom. It was more likely to find them frozen in the "bottom" position whereas they would run OK but not make the power they should. The Honda 250R system was more reliable, but would still stick. By the way, the pilot jet was my first suggestion, and we used torch head cleaners to clean them first as they are like a tiny rat-tail file. Use caution though as you can easily enlarge the jets as the brass is soft. THEN spray with cleaner. My final suggestion if yer bike doesn't have a variable port system, or it's working OK, is to check that your choke plunger isn't hanging open slightly. After I clean the plunger and barrel with scotch-brite, I use some wd-40 or better yet cable lube to lightly coat it before it's installed. This staying even slightly open will flood you on start-up, and run rich making lots-o-smoke and 4-cycle-ing on the bottom. There ya go. My 2 cents.

[Troll 2]

Maybe your bottom end is overfull on b.m. oil and hasnt burnt out yet. Matbe it will come around after the long ride?
I go by this theory;
Original post;
I found it here;
http://www.motocross.com/forum/topic.asp?TOPIC_ID=21626
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Pre-mix 101

OK, looks like it's time for a little pre-mix 101. I don't usually get into ratio discussions, because mix ratios are like religions to most people, and they tend to be closed-minded on the subject, but I'll put in my $.02 here anyway.

There is a prevailing myth that less oil is better, and that the oil in the fuel is what lubricates the engine. Both are wrong. The engine is lubricated by the residual oil that builds up in the crankcase. All the oil in the fuel does is replenish this oil.

The best way to determine if you are running enough oil is to check the level of the residual oil in the crankcase. If the ratio you run leaves enough residual oil in the crankcase to cover about 1/8" of the bottom of the crank wheels, then you are fine. If you don't have that much residual oil in your crankcase when you pull the top-end off, you aren't running enough oil for your riding style and conditions.
With that said, to have that amount of residual oil in the crankcase at 50:1 (a ratio made popular by magazines and oil bottles), you can't be riding very hard, or your bike is jetted richer than necessary simply to deliver enough oil. I arrived at 26:1 for my bike with my riding style because that is the amount that gives me the proper amount of residual build-up. Small-bore engines require greater oil concentrations than larger engines to achieve the proper amount of residual build-up, because they rev higher and have higher intake velocities. Along the same lines, someone that pushes the engine harder, and keeps the revs higher, also needs to use higher oil concentrations to achieve the proper residual build-up.

To understand why the residual oil is so important, you have to understand what happens to the oil in your fuel when it goes into the engine. While the oil is still suspended in the liquid gasoline, it can not lubricate anything. It has about as much lubricity at that point as straight gasoline. When the gasoline enters the engine, it evaporates, dropping the oil out of suspension. Now that the oil is free, it can lubricate the engine, but it must get to the parts to lubricate them. The way it gets to the bearings and onto the cylinder is by being thrown around by the spinning crankshaft. Some of the oil eventually makes it into the combustion chamber, where it is either burned, or passes out the exhaust. If the combustion chamber temps are too low, such as in an engine that is jetted too rich, the oil doesn't burn completely. Instead, some of it hardens into deposits in the combustion chamber, on the piston, and on the power valve assembly. The rest becomes the dreaded "spooge". The key to all of this working in harmony is to jet the bike lean enough to achieve a high enough combustion chamber temperature to burn the oil, but also still be able to supply enough oil to protect the engine. If you use enough oil, you can jet the bike at it's optimum without starving the engine of oil, and have excellent power, with minimal deposits and spooge. At 50:1, you simply can't jet very lean without risking a seized engine due to oil starvation.

With the high oil concentrations that I use, I tend to get far more life from my cranks and rings than most of my friends that run leaner oil ratios. The high oil content also produces better ring sealing, so more of the combustion pressure is retained.

One small point. No one ever broke an engine by using too much oil.

__________________________________________________ ____________________________________

Pre-mix Ratios and Horsepower Production

I have run Dyno tests on this subject. We used a Dynojet dynamometer, and used a fresh, broken in top-end for each test. We used specially calibrated jets to ensure the fuel flow was identical with each different ratio, and warmed the engine at 3000 rpm for 3 minutes before each run. Our tests were performed in the rpm range of 2500 to 9000 rpm, with the power peak of our test bike (an '86 YZ 250) occuring at 8750 rpm. We tested at 76 degrees F, at 65% relative humidity. We started at 10:1, and went to 100:1. Our results showed that a two-stroke engine makes its best power at 18:1. Any more oil than that, and the engine ran poorly, because we didn't have any jets rich enough to compensate for that much oil in the fuel. The power loss from 18:1 to 32:1 was approximately 2 percent. The loss from 18:1 to 50:1 was nearly 9 percent. On a modern 250, that can be as much as 4 horsepower. The loss from 18:1 to 100:1 was nearly 18 percent. The reason for the difference in output is simple. More oil provides a better seal between the ring and the cylinder wall.

Now, I realize that 18:1 is impractical unless you ride your engine all-out, keeping it pinned at all times. But running reasonable ratios no less than 32:1 will produce more power, and give your engine better protection, thus making it perform better for longer.




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or this?


Another way of thinking found here; http://www.macdizzy.com/oil2gas.htm



If you get the opportunity to take apart an engine very often you may notice that the bottom end of a two stroke almost always has a substantial amount of oil laying in the cases. Even in engines that have been run at leaner oil to gas ratios (50:1 to 100:1) there is plenty of oil. The other internal parts of the engine also are well coated wet with oil. It doesn't matter if the motor is air cooled or liquid cooled - the internals of the engine are still coated. Much of this oil may accumulate at idle and during periods of low rpm running. Once you get the motor spinning faster and it is under load, that extra oil in the case may finally have a chance to become suspended again in the fuel and air mixture and perhaps be burned.

Many people will rev their engine to clear that oil (that plume of smoke they get at startup or after idle) and refer to it as "cleaning out" the engine. And that is exactly what is happening. That oil - which has become separated from the fuel has gathered in the cases and is standing by waiting for some serious turbulence to get it up the transfer ports and into the cylinder where it can finally be burned. Too much oil in the gas can lead to additional problems like carbon deposits on the piston crown and cylinder head, sticky rings, fouled plugs and wet drippy black gunk (unburned oil) coming out of the joints of the exhaust system.

It is probably best to avoid sustained periods of idle, or very low rpm running under no load. It is also probably better to choose a lower gear (for instance 3rd at 5000 rpm instead of 4th at 3800 rpm) and let the motor spin faster when driving at slower speeds since there in less likely a chance of the oil not finding its way to the combustion chamber. It is my opinion that if you use top quality oils (synthetics are the best) you are only throwing away money and making more smoke by running more oil through the engine than it needs. I have had good luck by always using the same oil to gas ratio and the same oil brand.


Anyway it's interesting.........

[Wickedfinger]

.... I'm going to throw in it might be a crank-case air leak. You might have a bad crank seal. You do have a couple of the classic symptoms - erratic idle, plug fouling. Are you losing any tranny fluid or is any comming out of the breather?.

[Derrick Adams]

I agree with the choke plunger issue. I just changed mine, and you could definately see it was worn on the bottom. Might be worth looking at!

[Darius1502]

If I had a bad crank seal would'nt it be buring tranny fluid?

[Wickedfinger]

..... sure - the smoke, the fouling .... I'm not there, you have to tell me. Even a little bit of tranny fluid in your fuel charge will change it drastically. Check this out: Crank or other bottom end seal is defective, you are hard starting and hard idling because you are running way too rich from the tranny fluid - its not alot of fluid, but just enough to change things richer. You get it to rev up and it seems to run fine or at least better at higher RPMs. Conclusion - at the higher RPM's you might be also letting in an increased amount of air (from the leak) into your previously tranny fluid richened charge and now its changed back to a leaner or more corrected mix. Just a hypothetical guess, but thats what I got. If you can, do a high speed plug check and examine the plug. If you see alot of gray or dark "wicking" or small carbon like hairs - thats the tranny fluid not burning completely. Again, just a shot in the dark really.

[Darius1502]

Ok...If I rotate my crank with the cylinder off would see tranny oil on the crank?

Is this is way to check the seal?

How do I know for sure that there is leak?

[Lots_Of_Nothing]

Get it started and romp the hell out of it. You arent going to get anywhere untill you let the engine clear itself out. You can make 30 different posts about this same exact problem, and get 3 pages of replys, but that isnt going to fix nothing. Go try.

[bigredhead]

I think you can get the crank presurised and tested this way !!!

[Wickedfinger]

Ok...If I rotate my crank with the cylinder off would see tranny oil on the crank?

Is this is way to check the seal?

How do I know for sure that there is leak?
Yes and No - you are only going to see a small seal leak when the crankcase is under a slight vacuum or pressure - that turning the crank method might only work for a larger, obvious leak. You should really do a leakdown test. I would take it to a dealer and have them do it. Theres alot of "extra" equipment involved and if you put too much pressure in it (like over 5psi even), you will completely blow out the crank seals.

[Darius1502]

Get it started and romp the hell out of it. You arent going to get anywhere untill you let the engine clear itself out. You can make 30 different posts about this same exact problem, and get 3 pages of replys, but that isnt going to fix nothing. Go try.

I agree...I don't want to clutter up the board with this mess...if that does not help then it must be the crank seal.

[Darius1502]

I am learning alot guys...thanks.!!!

Here is a great bit on info on diagnosis from plug readings:

http://www.eric-gorr.com/techarticles/sparkplugs.html

[TimSr]

I agree...I don't want to clutter up the board with this mess...if that does not help then it must be the crank seal.

I shoudl have asked this question first. How long did you run it after you got it started? A good 1/2 hour of normal riding?

[Darius1502]

oK...now I may be in trouble with everyone.

I have to take the Z out to some land we own to really ride it. I live in a subdivision and can't run it for too long.

Ok Tim...I only ran the thing for about 10 minutes.

On the up side: this is a hell of an informative post and it very well may be the crank seal or little dirt thats trapped in the pilot hole.

[90nut]

would a bad crank seal cause the idle on my 84 tecate to idle normally and then just steadinly climb higher and higher?

[Darius1502]

That sounds like a air leak to me. This could come from a crank seal leak or a leak around the intake manifold.

[RideRed250R]

iam pretty sure its low compression, my R did the same thign be4 it blew up would start if pulled would run if * had throttle and then it just went POOOOOOFFFFFFFF goin up olds at glamis,
adam

[Rustytinhorn]

I know this is an old thread, but I'm wondering if you ever found a solution to your Z problems???

[300rman]

if you can pull-start it, run some SEAFOAM in the tank with some MARVEL mystery oil. it will further clean the carb out, condition rubber seals, and help eliminate possibilities.
if you run it, and your symptoms persist, it is doubtfully a dirty carb issue.

[brapp]

i jsut went trough this same isse with a broken woodrukk key on the flywheel it advanced the timign enough that if you spin it by dragign it that it woud run but run liek total crap and pulled the flywheel and it sure enough just my .02 cents.