my 350x is cursed.

[fcf35]

My first 350x.I was so excited to have the chance at getting one I bought one not running and have had headache ever since then.Guy filled me with crap saying it had a "factory 500 stroker kit and had been ported and polished.searched everywhere online and found no story on a factory 500 kit.all I do know is that is has a full cobra exhaust.it had stock jetting and all airbox components intact.I bought a new stator and cdi and it running but it will not run good.I have a 350x and 400ex Carb and have been trying both with different jets and removing air box lid.it running the nest I've had it since I put a 42 pilot and 142 main in the 400 Carb.runs fine till 3/4 then dies.while in neutral if you gag it it dies.you can roll in to it and it will Rev but as soon as it hits 3/4 its done.please help.

[barnett468]

Hello


So far it sounds to me like it is either jetted lean, cam timing is off one tooth, or has an air leak.


Did you install new gas or add gas to old gas?

How many hours has plug been in?

What color is plug, lite tan, dark tan, dry black, moist gooey black?

Can you do a compression test or does it feel like it has good compression?

You might check cam timing [see manual below] could be off because you have to gag it to make it idle..

Do you have a larger jet like a 150-160? If so try that.

How is spark at plug, weak pale yellow or strong lite blue?

How much choke do you use to start it, 1/4, 1/2, full?

What is air temp when starting?

Check for air leaks by spraying around intake boot at cyl head with flammable carb cleaner sounds like this may also be why you have to gag it to make it idle.

Check valve clearance.

Try with and without air box lid after installing larger main jet.


Service manual, just click blue line then select service manual.

http://www.kb0nly.info/ATC/index.php?dir=ATC350X%2F

[barnett468]

Might check ignition timing also. Remove plug in stator cover and lite should flash with F in center of window.

[barnett468]

Hello

I think i misunderstood your "gag comment. What exactly do you mean. If you cover the carb opening at isle it is suppose to stop unless it has a huge air leak.

How does it idle with no gaging the carb and no choke?

You may not have an air leak.

[dougspcs]

Difficult to know where to start with this many variables..you don't know the bike or the real state of the engine since you can't verify what the PO stated to you..

If you have been thru the carb route it may be time to look closer at the engine..definitely a base compression test, then for comparison sakes a wet test (a bit of oil in the cylinder and repeat compression test)

Besides the obvious carb issues..this may be from an improper engine repair, broken or weak valve springs, or exhaust restriction(you didn't mention the exhaust..stock or replacement)

Then it'll be time to verify the ignition components for issue related to ignition timing..

Nor did you mention if it smokes, hard to start warm or cold?

Best just start basic and work thru it..compression numbers to start?

[fcf35]

The bike takes 4 or 5 kicks to start.I put 350 Carb back on with a 42 pilot and 138 main.it will idle perfectly and run good until you stab the gas then it just dies.plug is new with new 93 octane in it.in neutral while idling if you slowly give it gas it will Rev up but if you blip it really fast it dies.I checked the can lastnight and the marks on the back of can sprocket don't perfectly line up with the head.looks like if I move chain in either direction on sprocket it will never line up perfect.with the T lined up on flywheel the mark on the right side of the sprocket is a little above the head and the left is a little below.valves are in spec.has good compression,my rightleg can tell you that.

[fcf35]

Full cobra exhaust,no smoke at all.with 350 Carb it takes 3-5 kicks with no choke.I took the header of and can see someone polished exhaust ports so probably is ported.it has massive exhaust pressure,it blowed full paint cans off me work table.the 350 Carb has been rebuilt.I tried a 155 main and it turned plug dry black but still cut out when I blooper throttle from ldle.checked intake boot with Carb cleaner and nothing happens.I can ride it down the rode with no problems unless I give it more than 3/4 throttle.

[dougspcs]

That is a reasonable start..

Maybe grab the manual and start some ignition troubleshooting.

http://www.oscarmayer.net/atc/manuals/

[fcf35]

What could cause my cam sprocket to not line up?chain is tight and I know my flywheel key isn't sheared.its an 86 and I'm running a 400ex cdi.I did notice when using a dr8esl plug the piston hits and closes my plug gap.I put a d8ea in it and it works fine?like I said the Guy told me it had a stroked crank in it but I'm not sure if you have to use a shorter plug in it.

[fcf35]

I have a manual but from what I've read the ignition is pre set from factory.I have a good stator and cdi.I check to see if oil was getting to stator and there is none.I seen in the manual to test ignition with timing light but if its off how do you adjust it?

[fcf35]

What could cause my cam sprocket to not line up?chain is tight and I know my flywheel key isn't sheared.its an 86 and I'm running a 400ex cdi.I did notice when using a dr8esl plug the piston hits and closes my plug gap.I put a d8ea in it and it works fine?like I said the Guy told me it had a stroked crank in it but I'm not sure if you have to use a shorter plug in it.

[barnett468]

Hello


“I checked the can lastnight and the marks on the back of can sprocket don't perfectly line up with the head.looks like if I move chain in either direction on sprocket it will never line up perfect.with the T lined up on flywheel the mark on the right side of the sprocket is a little above the head and the left is a little below.valves are in spec.has good compression,my rightleg can tell you that.”

Ok it sounds to me like you probably have either a worn timing chain at the very least or a different cam that just happens to have the sprocket pin or bolts clocked slightly different than your orig cam because it is from a different bike or aftermarket. I think this is unlikely though. Any cam timing that is retarded will partially contribute to your problem.

This is a quick and easy test


Remove plug from stator case, rotate motor until you see an F IN THE WINDOW. Clean it with brake cleaner and a q tip then mark it with white out, after it dries check it with timing lite. The F should be in the window at idle and disappear at high rpm. If F is not in center of window but instead to the left of the window it is firing AFTER tdc. Set timing so F is in window at idle.


If F is in window or you do not have a timing lite then simply remove pulse coil cover check mechanical advancer to see if it opens and returns easily without binding and that return springs are not loose. If that is ok then mark the position of the pulse coil then advance it slightly. Make sure to go the right direction, you can double check with timing lite. You want the F to be to the right of center of window at idle.


This may very well help your problem because you may have a larger than stock cam in it. It also typically helps when a cam whose timing is retarded due to a worn cam chain.


Install the bigger main you have and try it, if it’s not better raise the needle by lowering the clip, and raise the clip on the needle.


You should check cam chain tensioner and chain tension and replace chain sooner than later if it is excessively worn.

[fcf35]

My timing chain is tight.I just rode it and I choked it it fired off then I turned choke off and it fired right up.still same problem.riding at low rpm in any gear its fine but when I try to gas it for a wheelie it cuts out or when I get on it hard it cuts out.I'm fixing to try the needle first and then ill try a bigger main.all I have is 142,150,155 and up.I honestly appreciate everyone's help on this.I'm just ready for this thing to scream.I have 2 200x and another 350 with a new motor from my local school.I'm trying to save that motor for as long as I can though.200's are fun but leave me wanting more and I've had 2 250r but there not for me.they are wheelie machines but sometimes(most of the time)wheelie when you don't want them to.Im ready to see what a mildly modded 350 will do.and again I really appreciate Amy help that's been given to me.

[dougspcs]

What could cause my cam sprocket to not line up?chain is tight and I know my flywheel key isn't sheared.its an 86 and I'm running a 400ex cdi.I did notice when using a dr8esl plug the piston hits and closes my plug gap.I put a d8ea in it and it works fine?like I said the Guy told me it had a stroked crank in it but I'm not sure if you have to use a shorter plug in it.

I'm going a different way on this..perhaps the incorrect head gasket thickness for the work that was done to the engine.

The DR8ESL getting the gap smacked is a big red flag for me..that is the stock plug. If the piston is hitting it there is a clearance issue..could have dinged a valve? That may be where the symptoms are coming from..if nothing else improper clearance can change your cam chain timing..

Can you get hold of a scope to look inside the cylinder for any signs of strike on the piston face? Just to be sure.

[fcf35]

I checked again with new dr8esl and I didn't hit.put the old dr8esl in and it hit again.not sure if old plug was misprinted or what but with the new one its fine.

[dougspcs]

Well it's clear you have a cam timing issue .. you said it was off about 1/2 tooth??

You may want to consider pulling the cylinder head and checking that top end out up close. Maybe it has the wrong chain guide in it, maybe the keyway is damaged??

This mystery is getting weirder by the minute.

What did the PO mention about the way if ran?

[dougspcs]

I have a manual but from what I've read the ignition is pre set from factory.I have a good stator and cdi.I check to see if oil was getting to stator and there is none.I seen in the manual to test ignition with timing light but if its off how do you adjust it?

You don't adjust it..it will just tell if the spark controller is failing.

[fcf35]

Went to change jets and my needle seat fell out.was just trying to the jet itself out and the whole thing came out.I stuck it back in there and tightend everything sown but I'm not sure how far to screw it in.it has a nut on the threads that I assumed was for adjusting but I don't where its supposed to be at.

[fcf35]

If the cam is off will it still start and idle good?today I started with 42 pilot and 138 main and it would start and idle and run but only to 3/4.then I tried a 145 and it will start and idle but cuts out from 1/2 on through and runs telly rough.seems my dogs have knock all my extra jets all over so I'm still looking for that 142 to try.

[fcf35]

I know my keyway is good because I put a new one in when I put a new stator in.don't know how it ran before me because everything the Guy told me has been a lie so far.his exact words were that the motor was built in the early 90's and that it had a Honda factory ha5 500 kit in it and that it had been ported and polished.after he bought it he said he honed and replaced rings and only rode it for an hour or so after break-in.he said he was riding it with no issues when it just quit,like a light switch turning off.I bought it replaced stator and cdi and it would start and run but with the problems I've been describing.can chain is good and tight and only way to loosen is tightening the bolt.

[dougspcs]

If the cam is off will it still start and idle good?.

Well you mentioned it started in 5 kicks..mine starts in 2, 1 when warm..but other than that yeah it's run with the cam off one tooth.

But since all valve timing will also affect intake vacuum it'll play hell on carb jettings and adjustment it can't be ignored as a possibililty..

[fcf35]

Think I'll just have to bit the bullet and tear her down.the new motor I have will start on first kick but its in a 85 frame that needs axle bearings.sounds easy but someone thought I would be a good idea to weld both sides of the hubs on the axle.ah the joy of buying 30 yearold machines!!I honestly appreciate all the help on this and by the time I get it lined out ill have some useful info for someone else.she's going on the back burner till I get me some gaskets before I tear into'er.thanks everyone.

[barnett468]

Hello fcf35


Think I'll just have to bit the bullet and tear her down.


Before tearing it down you might try the following.


1. Try the 142 main jet or a 148 if you have one.

2. Check out electrical as suggested however if your plug has a strong blue spark then your system is most likely good.

3. Then if it still runs bad tear it down and measure cylinder height, piston to cylinder top height. If piston is a FLAT TOP or RAISED DOME and outer edge rises above the top of the cylinder at tdc then use thicker head gasket. If it has a raised dome piston and the outer edge does NOT rise above the top of the cylinder than either install a thicker head gasket, mill dome slightly around plug area or install flat top piston.

4. Throw that cam as far away as possible then either buy a stock one or a performance one that someone on the site has used with SUCCESS and recommends.

5. It may have been ported too much, it is possible. Porting is NOT just a simple process of making the holes as big as you can.

xxxxx

Guy filled me with crap saying it had a "factory 500 stroker kit


If it does have some sort of high performance piston this might account for the piston hitting the plug. If it has a stroked crank then it is possible the stroke, piston, rod combo is slightly than it should be allowing the piston to travel slightly higher in the cyl thereby causing the piston [that may have a raised dome on it] to hit the plug. The cylinder may have also been machined which would not only potentially cause the piston to hit the plug but would also account for your cam timing being retarded. Your head may also have been machined to increase compression which you suggest it has a lot of. It would be highly improbable that any aftermarket head gasket could be thin enough to allow the piston to hit the head on a stock motor however on one that is stroked, bored, has a milled head or machined cylinder it is possible.

You would really need to remove the head to check all these things.

FROM MY POST 2. - Can you do a compression test or does it feel like it has good compression?

It has a lot of compression then you fix a few possible problems if need be simply by installing a thicker head gasket. You can get one made if necessary. This would increase clearance between the piston and plug and valves and would at least partially correct you cam timing issue.

Xxxxx

I tried a 155 main and it turned plug dry black


Carb is rich but if this thing has a huge cam than that will contribute the the problem. Try the 142 or a 148 if you have it.

xxxxx

but still cut out when I blooper throttle from ldle.checked intake boot with Carb cleaner and nothing happens.I can ride it down the rode with no problems unless I give it more than 3/4 throttle.


As I previously mentioned it is possible that at least part of this problem is because it has a huge cam and the timing is not far enough advanced for it but since now know you can not adjust the ignition timing this info won’t benefit you.

Xxxxx

What could cause my cam sprocket to not line up?chain is tight and I know my flywheel key isn't sheared.


EXCERPT FROM POST 12 - Ok it sounds to me like you probably have either a worn timing chain at the very least or a different cam that just happens to have the sprocket pin or bolts clocked slightly different than your orig cam because it is from a different bike or aftermarket. I think this is unlikely though. Any cam timing that is retarded will partially contribute to your problem.

TIMING CHAIN – The fact that it is tight does not mean it has not stretched enough from wear to cause your cam timing to be off slightly. Didn’t you ever adjust a chain on a bike because it stretched from wear?

See comments above for additional potential causes.

xxxxx

I did notice when using a dr8esl plug the piston hits and closes my plug gap.I put a d8ea in it and it works fine? I checked again with new dr8esl and I didn't hit.put the old dr8esl in and it hit again.not sure if old plug was misprinted or what but with the new one its fine.


Your plug was not misprinted. The reason one hit and not the other is simply because one was clocked [indexed] differently than the other when installed ie once installed the electrode was in a different position and one position was closer to the piston than another. See comments above for further info regarding this issue.

xxxxx

What could cause my cam sprocket to not line up?chain is tight and I know my flywheel key isn't sheared.


EXCERPT FROM POST 12 - Ok it sounds to me like you probably have either a worn timing chain at the very least or a different cam that just happens to have the sprocket pin or bolts clocked slightly different than your orig cam because it is from a different bike or aftermarket. I think this is unlikely though. Any cam timing that is retarded will partially contribute to your problem.

TIMING CHAIN – The fact that it is tight does not mean it has not stretched enough from wear to cause your cam timing to be off slightly. Didn’t you ever adjust a chain on a bike because it stretched from wear?

See comments above for additional potential causes.

xxxxx

I did notice when using a dr8esl plug the piston hits and closes my plug gap.I put a d8ea in it and it works fine? I checked again with new dr8esl and I didn't hit.put the old dr8esl in and it hit again.not sure if old plug was misprinted or what but with the new one its fine.

Your plug was not misprinted. The reason one hit and not the other is simply because one was clocked [indexed] differently than the other when installed ie once installed the electrode was in a different position and one position was closer to the piston than another. See comments above for further info regarding this issue.

xxxxx

like I said the Guy told me it had a stroked crank in it but I'm not sure if you have to use a shorter plug in it.


It certainly looks like you do for now however an alternative would be to simply add another crush gasket to the plug to space it further away from the piston.

Xxxxx

I checked again with new dr8esl and I didn't hit.put the old dr8esl in and it hit again.not sure if old plug was misprinted or what but with the new one its fine.


TIMING CHAIN – That that it is tight does not mean it has not stretched enough from wear to cause your cam timing to be off slightly. Didn’t you ever adjust a chain on a bike because it stretched from wear?

xxxxx

I have a manual but from what I've read the ignition is pre set from factory. I seen in the manual to test ignition with timing light but if its off how do you adjust it?

You don't adjust it..it will just tell if the spark controller is failing.


Well isn’t that just lovely.

[fcf35]

Thank you barrnett468 for all your info.I've decided to just tear it down because I've tried several jets from 138 to 165 it ran like crap with every one of them.I'm gonna go over it the best I can and see what's really in this motor.I do have a parts motor that has a good head and new 10.25 piston.I am a little worried about that porting because he told me that when he put new rings in he did some "extra" porting to it.Im just dreading yanking that Titanic boat anchor out of there.I got my new axle and bearings for my other 350 I just have to grind the welds on the other axle to get it out.I was just hoping the 86 really had some good upgrades so I could show some of these late model big bores that 3 wheelers really are bad@#$.what's some good tips on getting my stock 350 ready for some z440's?I already have a full exhaust to put on it and a k and n filter or uni.

[fcf35]

Does anyone know if any of the bigger cams from any company or the xr 500 cam would cause my cam sprocket marks to not line up with my head?I'm still trying my best to diagnose this motor before I have to tear it apart.

[yaegerb]

My guess is the previous owner advanced the cam timing and that's why its bogging when you stab the throttle. Bust out the manual and re-time the cam dead nuts to 12 o'clock. See how it runs after that. If that doesn't work I would say you have something wrong in your ignition.

[fcf35]

That's my problem.only way I could adjust the cam is to move the chain over a tooth but it still wont line up when I do.its like its only a half tooth off.I just got another 350 and its "really" wore out with extremely loose valves and a cam chain that you can here over the motor running but it starts first kick and runs 0-full throttle just fine.the only thing I've done to the 'supposed'big bore motor is replace the flywheel and stator.its a 86 motor but the flywheel I put in it is from an 85.it has nd stamped on it.the cdi I have is a aftermarket 400ex cdi.

[fcf35]

From what I've read the 85 and 86 have different flywheels.I read that as long as you use the sameyear flywheel and stator it would work.the stator that came out of it when I got it was the same kind I replaced it with.

[fcf35]

Hell yeah boys!!!!!my two 350's are back from the dead.turned out to be my carbs I had.I got me two good 400 carbs and they both run like hell now.my stock motor with full exhaust is running on a 40 pilot and 146 main and my supposed big bore is running on a 42 and 155.the big bore bike pulls about 8 bike lengths over the stocker so I know there's something done in there and that's with bald tires.if they had tread I don't think the front end would stay down at all.I can't believe it though I cleaned and rebuilt my tester Carb numorus times and it turned out to be junk.I'm so happy now that I don't have to tear into the bigbore motor.both start within 2 kicks and run awesome.the stock Carb with stock jetting wouldn't even think about running a fully piped motor at all.the 400 Carb and full exhaust is absolutely. No comparison.