Would you adjust valves if out by .01?

7 replies to this topic
  • RichFZR-WR

Posted July 14, 2010 - 12:49 PM


Hi all, as the title says, just checked my valves on my wr426 and found that 2 were .01 out and 1 was on the high side of the limit, is it worth adjusting now.

EX .26 .26 states EX 0.20-0.25
IN .11 .11 .15 IN 0.10-0.15

Looking for some feed back as to whether i should adjust now for such a small tolerance out or not?

Is it better to be on the high side or the low side of the valve clearance tolerance?

Cheers Rich.

  • jw423

Posted July 14, 2010 - 01:19 PM


I would adjust anything out of spec, to as close to the middle of tollerances as possible. With it being something you can't just keep an eye on all the time. You may bend one of the valves and that is much more costly and time consumeing. Also the specs are there for a reason. If .01 is O.K. then is .02 etc?

Just my opinion though. Some people don't even check them, so there is that.

  • Live 2 Ride

Posted July 14, 2010 - 01:26 PM


I would say as long as their in spec from manufacture or in spec to whatever the pros say (like on crf250 to run the ex sides tighter Ect.)

As close as possible to normal is best.

And remember all that stuff expands and such and alot does at diffrent rates.

  • Flagstaff

Posted July 14, 2010 - 07:18 PM


Shims are usually cheap, some dealers swap them straight accross. you allready got the bike apart, so? I try for center of spec.

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  • Just_a_trail_rider

Posted July 14, 2010 - 08:56 PM


I would adjust the valves if they are out of spec, even by .01

btw... how do you measure a valve being out by .01? You must be combining your feeler guages.

here's the deal... no single shim will be enough to take you from being tight to loose according to the spec. If you valves are tight (normally the case), then you can probably go up a shim size and still be in the middle of the spec range.

anywhere withing the spec range is acceptable.

Valves out of spec have the potential for bad performance and disaster.

  • 123BigcoopDawg576

Posted July 15, 2010 - 06:21 AM


btw... how do you measure a valve being out by .01? You must be combining your feeler guages.

+1 :smirk:

Never thought of the combining one before...

  • RichFZR-WR

Posted July 15, 2010 - 11:58 AM


Thanks for the responce guys, think I'll adujst the valves that are slighty out after the feed back given.
Always conbine feeler gauges to get an acturate measurement on valve clearences?
Why, how do you guys check to be acturate.

  • WR_Dave

Posted July 18, 2010 - 06:28 AM


The first time I checked the valves on my old 426, I got them all back to normal ( near the middle of the spec) by swapping the shims around that came with the engine. Just so you are aware, valves normally get tighter as they wear in, the two that would concern me the most are the 2 intakes that are close to the minimum clearance. Exhaust valves run hotter than intakes so having them at the loose end of the spec is better. As for checking valves, I use a good set of machinist feeler blades ( that I got from the UK by the way - they have the thinned tips so they fit better) that have very small differences between the sizes for more accuracy. WR Dave


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