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Starting/Idling issues.... any advice?

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Well, I checked my valves today and my right side intake was a little on the tight side at 0.09mm so I swapped out the 2.55mm shim for a 2.50. I put everything back together double and triple checking all the timing settings (29 chain "pins" at TDC) and tightening everything to spec. I put the gas tank back on and hooked up the fuel line and then attempted to start the bike.

Starting it was a real PITA!!!! It had plenty of compression and would try to kick over a couple times but would then die. It finally started, ran and then popped through the intake and then died. Subsequent attempts to start it mostly failed and I was getting a few backfire pops at the bottom of the kick start stroke. I was able to get it started a few times and even rode it once, where it seemed to run great!

The times I was able to get it to start, I had to give a twist of the throttle and then hold the hot start open. This would eventually get the engine to fire and then I was able to hold the throttle open a little to keep it going. If I let up on the throttle, the engine would die within 5-10 secs, with a small backfire pop through the intake. I checked my fuel screw and it was two turns out. I even turned up the idle a little and that didn't help.

The last time I ran was last Sat. at the track and then again once I got home and it was running great. Not sure if a week of sitting would have caused this but my guess is that some how, some way, I got something out of whack!!!

Does anyone have any clues as to where to start in diagnosing the problem?

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Just curious as to why you changed the shim's if it ran great?? I would pull the valve cover and plugs off and recheck the marks. If they line up correctly I would suspect the shim is the problem. I would put the old shim back in and see what happens. :thumbsup: I have yet to take mine apart. I checked the valves at 50 hrs. and they were still tight. I have 65 hrs. on her and still no problems. If it ain't broke don't fix it?? :ride::applause:

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Just curious as to why you changed the shim's if it ran great??

Yeah, I've been asking that question myself.... :applause:

I would pull the valve cover and plugs off and recheck the marks. If they line up correctly I would suspect the shim is the problem. I would put the old shim back in and see what happens. :ride: I have yet to take mine apart. I checked the valves at 50 hrs. and they were still tight. I have 65 hrs. on her and still no problems. If it ain't broke don't fix it?? :applause::applause:

Yeah, I think that is my next step. BUT, that also means I'll be putting my valve back outta spec. I'm concerned that this may also not be a good idea. :applause:

What to do, what to do? :thumbsup:

Hopefully I'll have time tomorrow afternoon after I get back from a Sunday ride on my street bike to tear it back down and see if I can figure this thing out. I'll post up my findings when I have them.

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Well, I checked my valves today and my right side intake was a little on the tight side at 0.09mm so I swapped out the 2.55mm shim for a 2.60.

If your valves were too tight,you need to go down on your shim size NOT UP.

You should have rechecked the clearance after you shimmed,it would of been caught. Also, go by the pin count once you have the punch marks level on the cams, with the head surface. You can have the right pin count, but the timing can be still off,very noticeable with the punch marks though.

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Well, I checked my valves today and my right side intake was a little on the tight side at 0.09mm so I swapped out the 2.55mm shim for a 2.60.

If your valves were too tight,you need to go down on your shim size NOT UP.

You should have rechecked the clearance after you shimmed,it would of been caught. Also, go by the pin count once you have the punch marks level on the cams, with the head surface. You can have the right pin count, but the timing can be still off,very noticeable with the punch marks though.

Sorry, typo, I have since fixed it in my original post. I went to a 2.5 and I did check the clearance after I put it back together. And yes, the punch marks lined up with the pin count.

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Ok, I've got the bike running again. I tore it all back down and then put it all back together. The only thing I can think that was wrong was I might have been off on the timing by a tooth on the intake cam shaft.

So, what are the chances that I bent my valves with the timing being slightly off and having started and ran it in its previous state?

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Ok, I've got the bike running again. I tore it all back down and then put it all back together. The only thing I can think that was wrong was I might have been off on the timing by a tooth on the intake came shaft.

So, what are the chances that I bent my valves with the timing being slightly off and having started and ran it in its previous state?

One tooth shouldn't matter. You would know right away if you bent a valve. It would be way down on power.

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