02 YZ 426 decompression lever locked motor

3 replies to this topic
  • Pyro

Posted March 30, 2005 - 09:20 PM


Hey peeps I have an 02 YZ426 that had the decompression lever pulled while it was running. The engine made a tapping sound then the kill switch was hit. A few moments later (less than 3min) ,when the kick starter was being kicked, on the 2nd kick she locked up. The kick starter would not budge. Anyone know what might be messed up?

  • 02YZ426

Posted March 30, 2005 - 09:24 PM


Maybe a bent exhaust valve?? or could be a problem with the kickstart assembly.

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  • Scotty426

Posted April 01, 2005 - 08:40 AM


I hit my lever while the bike was running with no ill effects (I'm not advocating it). Think about it-it's made to hold open 1 exhaust valve just a hair to bleed compression and is clearanced so you can kick the motor around at any point in its rotation and not bang a valve. It will stop the motor (lack of compression) but shouldn't hurt it. It could backfire because you are bleeding a little air/fuel into the exhaust pipe. I asked my service guy at the dealer this question and he agreed. Does the decomp lever feel the same? I couldn't kick mine with brute force without moving it off top dead center with the lever. Could the decomp lever be not moving enough? That would be a cheap fix. Does the motor move with the lever in or is it truly locked? I recently went with the hotcams decomp exhaust cam and pulled the mechanism out since I no longer need it. It has a very small bolt with a C shaped end that functions as a cam to push the valve. It's hard for me to imagine how it could malfunction, push too far and cause the piston to bend your valve. This is good news. Good luck to you brother.

  • grayracer513

Posted April 01, 2005 - 09:38 AM


You may have bent or broken the right exhaust cam follower and/or caused it to jam in its bore, leading to the exhaust valve hitting the piston. See my post in this thread, 5 down.


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