06 yz450f smoking a bit

3 replies to this topic
  • erich4482

Posted December 05, 2009 - 08:12 AM


I just bought an 06 450f 50th anniv edition for a rather cheap price, and the guy seemed very meticulous about it, adjusted valves himself, kept the oil changed. It has a weighted fly wheel on it and thats about it motor wise. I went riding yesterday and it smokes just a little bit, and kinda smells like oil burning...also after a rev in neutral or in gear while moving, it wants to stay idled up for about 3 seconds before it falls back off to normal, therefore when moving when you back off the throttle, the engine doesn't scrub off speed like it should, it keeps pulling. Could the idle problem be simply in the cable ? And is the smoke possibly caused by the need of a new piston ring or something else ? Thanks for any help given.

BTW this is the first thumper I have owned, last bike was a 99 CR 250 about 7 years ago so I haven't learned a whole lot about them yet.

  • grayracer513

Posted December 05, 2009 - 10:51 AM


The idle hangs either because the pilot screw is adjusted lean, or because the intake valves are tight.

Smoke could be rings, but you may want to double check that there is not too much oil in the engine.

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  • erich4482

Posted December 05, 2009 - 03:24 PM


thank you. So if I adjust the pilot screw to make it more rich, is that going to cause it to smoke a little more ?

  • DangerRanger245

Posted December 05, 2009 - 08:27 PM


No what gray is suggesting is two separate issues.
Run your bike for a minute,shut it off, let it sit a minute and check the oil on the dipstick.
Adjust the pilot screw out, which yes would make it richer and see if the hanging idle goes away

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