Checked my valves Saturday intakes were at.009 exhaust at .010. Well past the legal limit.Where can I go to get shims for the valves, do you buy a kit or specific sizes? Should I replace the timing chain as well? With my valves this far out of adjustment I have noticed a significant loss of low end power.



I can clearly see you have been blowing off your maintenance. Shame on you, silly boy!

First off, follow your manual. You have already measured your clearance. Your next step is to accurately record the valve clearances. Next, you will have to remove each shim. On the shim is a number. Write this number down immediately w/ the clearance you have already measured. Using the chart in your book, you now locate your required shim. Write this down as well. Then you go to your Yamaha dealer or mail order, and order them. Then you wait 3 weeks before they show up. Install the new shims and "Voila", YOU ARE DONE.

Howard: I find it odd that your lash is loose instead of tight. Makes me wonder if your cam lobes are wearing. My valves are on the tight side, which makes sense to me since the valves go deeper into their seats as time goes by. Did you notice any clicking sounds coming from the head area? Seems that if the lash is too great, the cam lobes would tap against the buckets when they are at their loosest. Does it work this way? Anyone?

[This message has been edited by Boit (edited 11-05-2000).]

Howard to do a correct valve adjustment you will need a YZF426 :)


ps It an't the bike loesing power it's you riding faster [i.E. need more power]

i remembered when i had done mine the manual was incorrectly showing the intake and or exhaust cams on one page, or something along those lines...i don't have access to my manual, but if someone could shed a little light it might help as well. just as a precaution. i think it was in the inspect and adjust section.


I've never done this sort of maintenance. How often should valve clearance be checked? How do you know when something is outta whack? Is this fairly easy to do?


99WR,WR timing,throttle stop removed,Uni filter,E-Series pipe,carbon air box,Pro Tapers,lights removed,YZ tank,13 tooth sprocket

Howard does have pretty loose lashes and lobes!

Sorry. I don't really know what that means.


Your dealership definately should have shims for your bike Howard.

The owners manual is excellent for giving you the adustment steps.


[This message has been edited by Bryan (edited 11-06-2000).]

Who would of thought the thing would run this long? I was expecting a complete overhaul not just a measly adjustment... Three weeks? can't I just advance the timing to make up the difference? Lets see... where's that timing light :D Time to read the book and scratch my head. Never was too good with charts. If all else fails I'll take Monty's advice :)

thanks, huge

Hey Huge,

I just replaced my valve shims on the weekend. It is relatively straight forward job and is something that is not that technical (even for someone as mechanically inept as me). I recommend covering your frame above the motor in plastic to avoid dirt falling into the motor. When you measure the valve clearance be sure that the feeler gauge is "square" when you insert it under the lobe or you will get an inaccurate measurement. Use a magnet rod to lift the valve buckets. I just bought one specifically for the job - bloody sensational tool. Beware of the 12mm bolt hole central to the chain tensioner. I stripped mine out very, very easily. The chart is very easy to use. Just cross reference your paticular valve clearance with the particular shim number and that is the shim needed to be ordered for that particular valve. Thanks to Boit who gave me some helpful hints. Good luck to both yourself and Scott.


Grum :)

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