check valve clearance

6 replies to this topic
  • chainy

Posted January 22, 2012 - 07:43 AM


I have an 09 kx 250f and it starts fine cold but warm its a bitch, anyway I'm checking the valves for the first time and how much pressure do you use to get the feeler gauge btween the shim and lobe. I have to push pretty hard to get them in and it feels like I'm opening the valve by doing it. I'm very mechanically inclined and it I don't think you shouldn't need that kind of pressure. I would think light pressure in and out. nothing that flexes the feeler gauge, right? Shimming seams pretty simple but it looks like you need the proper reading to get it within spec.

  • antleo

Posted January 22, 2012 - 07:49 AM


you are correct you dont need a lot of pressure.

  • T.RexRacing

Posted January 22, 2012 - 08:09 AM


If you need some pratice on :"feel" use a micrometer and set it to .010". Then wipe the .010" feeler clean and insert it into the mic. That's how I learned and it's served me well for a long time.

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  • William1

Posted January 22, 2012 - 08:15 AM


The feeler shold slide in, minimal drag. Not forced nor slip in with no effort. You have to ensure you go straight in and not at an angle as they can confuse you. Be sure the lobe (the 'bump') is pointing AWAY from the vavle stem/bucket 180 degrees.

If you force a feeler in, it will take about the same effort to force an even thicker one in. Once in, feel the drag. Go down in sizes till teh drag barely goes away. That will be the size. Next thinner will feel loose.

  • Limelight

Posted January 22, 2012 - 08:18 AM


T.REX, nice suggestion... I just went in the garage and tried that one. Very clever. I wish I'd thought of it. :smirk:

  • chainy

Posted January 22, 2012 - 09:20 AM


thanks guys, i'll go check them out.

  • still2smokin

Posted January 22, 2012 - 11:53 AM


You could also pick a "go-no-go" feeler gauge set pretty cheaply and any auto parts store.
They are great if you havent used feeler gauges much, they have the size you want at the
tip then .002 thicker about a half inch in.

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