Valve adjustment issues...

Well, bought a used '00 650R from a friend last spring and rode it all summer. The bike ran like a swiss watch and pulled hard but never having a valve adjustment I thought i'd tackle it myself. Did a search on this forum and Off-Road.coms article and it seemed easy enough in theory.

They seemed a little tight, couldn't get a .15mm in the intake or a .20 on the exhaust. So I loosened them up a little, so that the feeler guage would drag a little and was all proud of myself. Put it back together, went to fire it up and voila'! Nothing. Wouldn't start. Normally starts 2nd or 3rd kick when cold. Jump started it in front of the house and it barely ran, sounded like a sewing machine, missing parts, going through a cat.

Question is, are the valves that sensitive to adjustment? My feeler guage jumps from .15 to .18 so even though they recommended .152mm for smack in the middle of tolerances I used .150mm. I'm tempted just to take it to the dealer and let them do it, not sure how much "drag" is enough. Any ideas would be greatly appreciated!


There's a lot of talk about how much drag is right on a feeler guage. The rule I know is if the next size up fits, it's too loose and converse for the next size down. I just did an adjustment on my 05 at 1000mi, and the same thing for me. The exhausts were really tight and the intakes were somewhat tight. So I left them just barely loose but not to the next sized guage. Also, I just rode this am in 23f weather and the thing seemed off. So I pulled the thermostat and found it stuck open. I replaced it with a Napa #115. Just FYI, and there's lots of discussion about that toopic also.

And as far as the starting issue, you sure you didn't leave anything undone when you pulled the tank?

The auto decomp was activated when you set the valves. You're going to have to redo the valve adjustment and make sure the stroke is set right before you set the valves.

Thanks for all the suggestions fellas.

XR4DEZ, your right. I called the dealer, again, and got a real life mechanic with more than 3 seconds to spare. He said the same thing. Right exhaust valve decompression mechanism is the problem, he said its an easy mistake the make. I'll tear her down and do it again, thankfully it doesn't take that long..unless you do it twice! How do you know its not activated or in the right part of the stroke for adjustment besides being TDC? Is there a trick? Obviously this is my first time messing with valves.

It was cold here too, 25F but I didn't think of the thermostat issue, the bike didn't run long enough to get warmed up properly.

Take off the stator cover. Make sure the comp release lever is slack and not bound up. Rotate the crank around counter-clockwise and you'll see the intakes open and close and then the exhausts. Line up the TDC mark when the valves are closed. If in doubt, go around again. When the valves are closed, the comp release should be a non -issue. Set the clearances and you're good to go.

Take the spark plug out and turn the flywheel the direction it turns when the motor runs. Watch the intake valves , when they open and then close You will be commin up to true TDC comp. stroke. Then turn the flywheel backwards slowly and listen for the RT EX rocker to click when it does the auto decomp will be off. then turn the flywheel back to TDC and make your valve adjustments. You can visually see if you have made the adjustments right with the Decomp off by looking at the amount of threads above the lockdown nut. Both Left and Right EX should look close to the same. If the RT EX has way more threads above the lockdown nut then the LT EX then it wasnt off auto decomp. Hope this helps

Great suggestions, thanks, i'll redo today.

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