Valve Clearances

6 replies to this topic
  • dwby2kwr

Posted February 11, 2001 - 08:39 PM


I have a 2000 wr that i rode all summer. Not nearly as much as most of you guys though. I am more of a weekend short ride warrior. well as you can probably guess i have it all torn down since its kinda cold right now. im doing all the lubing and cleaning and checking on it. I just got to the valves tonight. the intakes are perfect but the exhausts ar a little tight. I measured both to be about .23 mm. the book calls for .25-.30 mm.
So my question is, is this something to worry about? Has anybody out there burned any exhaust valves? I really dont want to take the cam out but i dont want to screw the valves and have to do a whole head job either. Any input on this will be greatly appreicated.

y2k wr, 13 tooth front,
airbox lid and baffle removed, 180 main, 45 pilot, 426yz er needle,
wr timing

  • MN_Kevin

Posted February 11, 2001 - 09:47 PM


I think the shims are $5/a whack. Cheap insurance for preventing engine damage.

  • kmcbride

Posted February 12, 2001 - 04:58 AM


I would address tightness now with 5mm downsize of pads. The tendency I have experienced is that of continued tightening over time, although slight. Check carefully the current pad size in the bike as many have odd sizes from the factory. Prepare to wait if you need to order as many sizes are on back-order through Yamaha. An option would be have a machinist grind down your current pads to the size you need.

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  • Dougie

Posted February 12, 2001 - 01:12 PM


Another tip, try to trade them with your dealer. There is a dealer here in Denver (Vickery for the CO boys) that will trade straight up. No cash needed. That is if they have the sizes in stock. You may have to wait for them to arrive.

  • Guest_Guest_*

Posted February 12, 2001 - 11:17 PM


don't machine the shims down as they are case hard and the harding is only 003" thick and after a while the tappets will loosen.
I machine down a exhaust shim and after 10 hrs i could hear a loose tappet again .On inspection the valve stem had made a small indent into the the right parts for the job!

  • Guest_Guest_*

Posted February 13, 2001 - 05:51 AM


Are they out of Yamaha's recommended specs?

Then do it right.

Follow the instructions in the manual to fit the proper shims.

This is probably the only hassle there is to owning a 4 stroke... and once you set them correctly... they might be good for the rest of the time you own the bike.

If you don't... You might end up sorry you didn't.

Just be glad it is not a four cylinder.

  • SFO

Posted February 13, 2001 - 09:54 PM


After working in a motorcycle cylinder head shop for a few years I can safetly say ignoring what is going on in your head is going to make some pro a rich man...
Now this could be construed a few ways...
What exactely is the dillema with adjusting your valves?
Set and forget.


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