'06 450F, valves adjusted, now wont start, super stiff kickstarter

5 replies to this topic
  • GHILL28

Posted June 13, 2012 - 11:56 AM


I just adjusted the valves on an '06 YZ450F, and ensured the cams were aligned both with one another and with the crank, and that the cam chain tensioner was functioning properly (per the manual). Got the bike back together, and there is a TON of friction at the kickstarter. At first it wouldn't even turn. Started to move slowly and is kinda moving easier now but no firing at all.

The bike sat for a good 4 months or so before that, so I put in some new gas and cleaned the jets out with carb cleaner. It started fine before all that.

Any ideas? Trying to go ride today!

  • grayracer513

Posted June 13, 2012 - 12:36 PM


Pull the spark plug, remove the center timing plug, and try turning the engine with a wrench on the crank. Easy or hard?

If it seems hard, is it A) hard regardless of crank position, or B ) are there particular spots within two full turns that are harder?

If it's B, recheck your cam timing.

If it's A, then I have to ask how you bolted down and torqued the cam saddle caps. It's extremely easy to distort these if you pull them into place by tightening the bolts, and/or torque them out of sequence or too tight. The correct procedure is to align and fully seat the caps by hand only, tightening the bolts only after the caps are all the way down in place. They have to align with the bearing alignment half rings and the locating dowels in the head. If you suspect the caps, loosen them and see if the engine turns freely. If so, you may need to have the head repaired.

  • GHILL28

Posted June 13, 2012 - 12:43 PM


Nm, it was the way I was installing the tensioner. Let out the tension too early and put a whole bunch of drag on the chain. Started right up, ran around for a bit, then died and now not starting, but the kicking is feeling as it should. Separate issue I guess. Has gas, has spark, has compression. Not sure what it is past that now.

The cams all spun very freely in their journals once I clamped everything down. The caps were seated by hand first so the dowels went in straight, and the semi-circle clips were in place properly.

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  • GHILL28

Posted June 13, 2012 - 01:06 PM


So it will fire up for about a second if I crack the throttle right as a kick it - give it some fuel squirt basically. Any ideas?

  • GHILL28

Posted June 13, 2012 - 01:39 PM


Just popped head cover to verify the timing, that's all good (chain didn't jump).

Is it possible to flood these things? I was kicking it a lot.

  • GHILL28

Posted June 13, 2012 - 02:27 PM


Found the problem....the pilot jet had fallen OUT. All gravy now.

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