To reshim or not (valves) yz 426

4 replies to this topic
  • byw

Posted June 15, 2006 - 05:49 AM


I checked my valves on a 2001 426 been having a plug fouling problem.Intake all check out at a tight .10 mm exhaust are at .20 mm.Now should I go ahead and reshim even though they are still in spec.I'm thinking the tight intake valves might be leading to my plug problem.Thanks in advance.

  • grayracer513

Posted June 15, 2006 - 07:44 AM


If you reshim them while they are in spec, they'll be out of spec, unless you use half size shims from Honda.

You say "tight .10". Be honest, is it a tight .10, or is it a .09? If it's a .09, it's out of spec, and you should shim it. If it's a .10, leave it, and come back in 6-10 hours to check that they are holding at that clearance.

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  • byw

Posted June 15, 2006 - 07:59 AM


I thought the shims came in .05mm that would put me from the bottom of the spec to the top I could be wrong that has happened before.I was thinking being on the loose end would be better then the tight end.The .10mm gauge fit pretty snug the next one I have is .076mm (.003in)and that does fit okay.Thanks

  • grayracer513

Posted June 15, 2006 - 01:59 PM


They do come in .05's, but both .10 and .15 are in spec, so there's no point in it. The drag you get on the gauge should be about like what you'd get if you held a 1" combination wrench on its edge by one end and had the other end sitting on a feeler gauge and then pull the gauge out from under it.

Another thing you can try... most gauge sets come with a .002 and a .0015. Combine them to get a .0035 (.089mm)

  • byw

Posted June 16, 2006 - 05:14 AM


Grayracer I went out and bought another set of feeler gauges last night the one set I had went from .15mm to .10mm nothing in the middle.So I picked up a better one and figured out that they are .115mm intake and .22 exhaust.After looking at the difference from low to high I realized that is a very small margin.So I put it all back together and will check them again after a few more rides.So tight valves weren't causing my plug fouling trouble where to look now.Jetting is 162mj,42pj,clip on needle up one.Coil maybe?Thanks for the help. :excuseme:

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