Checking Valve Clearance. Properly using feeler gauge?

8 replies to this topic
  • MotoSarge

Posted December 21, 2012 - 10:37 AM


Hey guys,

So this is probly a really stupid question, but I'm going to ask anyways because it's not making sense to me. I watched online on measuring valve clearance and I understand how to do it by taking the feeler and going under the cam lobe. My thing is.. none of my gauges fit.. For example the exhaust side on my bike calls for .20 - .25 to be in spec. I can take my .05 feeler and it doesnt fit. I cant see the valves being off this much. The bike is a 2012 YZ450F, with around 30 or 40 hours I would say. Its my first time checking valves since I bought it. Now when I use the feeler.. should it go all the way through the cam lobe and come out on the other side? because right now even the smallest feeler I have goes in about half way and stops. And yes its TDC and everything is correct and I can read decimals correctly. My guess is yes the feeler should go all the way through and have a slight drag when doing a back and forth motion. But I mean... damn... a .05 wont even fit??? thats crazy to me. Same goes for intake. It calls for .10 to a .15 for in tolerance. and my .05 wont fit. The bike ran fine and started in 1 or 2 kicks. Am I doing it wrong or should I get a smaller feeler gauge?

  • szebo

Posted December 21, 2012 - 11:06 AM


did you verifty the piston is in TDC?
oops i see u verified tdc.

Edited by szebo, December 21, 2012 - 11:09 AM.

  • szebo

Posted December 21, 2012 - 11:17 AM


not sure about other bikes, but hondas the TDC must be on the exhaust stroke. did u verify that its TDC on the correct stroke?

  • MotoSarge

Posted December 21, 2012 - 11:37 AM


Ok got it! I only had the marks inside the ignition cover lined up, I didnt even think about the marks on the cam shaft LOL. I knew this was a dumb question. Valves looks good. 1 Exhaust valve was a tad under spec, but other than that shes at .10 for intake and .20 exhaust!

Thanks for the ideas guys. I didnt even think about those darn cam marks.

Edited by MotoSarge, December 21, 2012 - 11:38 AM.

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  • szebo

Posted December 21, 2012 - 11:56 AM


yeah, u must have been in the wrong stroke.

  • William1

Posted December 21, 2012 - 12:00 PM


This post does not belong the jetting area.

You do not have to even look at the flywheel matrks.

Remove the fuel tank, remove the spark plug. Put the bike in top gear and slowly roll it forward. When the cam lobes are at 2 and 10 o'clock, check the cleaances.

  • MotoSarge

Posted December 21, 2012 - 02:43 PM


Sorry william. I didnt see an engine forum.

  • William1

Posted December 21, 2012 - 03:19 PM


LOL, there is no generic engine forum. This one is 'as good as it gets'! :)

  • singletracmind

Posted December 21, 2012 - 04:01 PM


Glad you got it figured out.

Edited by singletracmind, December 21, 2012 - 04:03 PM.

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