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2004 crf 250x tapping/knocking

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I have a question for anyone that might know about the 2004 crf 250x. I started my bike to let it warm up and I took it off the choke and it wasn't fully warmed up. The motor started making a chattering noise before it stalled out. I restarted the bike, idle was low, chattered again, it stalled and made a clank sound. Like the motor had kicked back. I tried to restart the bike and it backfired out of the pipe. I tried one more time, the bike started up and started making a tapping/knocking sound. I shut the bike off instantly, I pulled the valve cover off to make sure there was no problem in the top end. Everything looked fine. I spun the motor over a few times with the valve cover off. I placed the valve cover back on, put the coil wire back on, I started the engine and it was now running perfect, no noise or anything. I'm trying to find out what the noise may have been. Worried that I should booking for a bigger problem. It seems to run perfect right now though. If any input of what it could have been please let me know. Thanks.

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Probably the auto compression release, when it operates the exhaust valves close suddenly and the valve mechanism makes a clacking noise.

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i had a ktm years ago in which the de-compressor use to make a noise now and again,or stick which would be scary backfireing etc ! i just free'd the cable which operated it by lubing it every so often ....keep an eye on it but i would think thats what it is ..

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Basically, it sounds like you took it off the choke too soon which caused the idle RPM to drop below normal and caused the automatic compression release to rattle. I never knew how much noise it made until I cut my air box. Now it sounds like a fork in a garbage disposal for a second every time I hit the kill button. It took me a while to figure out what it was making all that racket.

 

Kudos to you for shutting it down and investigating immediately, instead of standing there while your bike grenades.

:thumbsup:

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