New yz426 a little help please.

5 replies to this topic
  • gasgasser

Posted December 07, 2009 - 02:26 AM


Just picked up a 01 426 that needs some tlc to get it back into shape again. While going over it I noticed a couple of things that I haven't com across on a 4stroke so far.

I dropped the oil and it was really dark and thick, and well over due for a change, when I came to change the filter I was alarmed at how many metal filing there were there, possible 1/3 of a tea spoon. I've never seen as much as that before as my oil changes are normally every 5hrs, anyone seen this or would be overly concerned?

The other is when I checked the valve clearance they were all tight. Again I have never had any on my bike go out of spec. Is it ok to shim them to bring them into spec or should I be really putting new valves in???

  • gasgasser

Posted December 07, 2009 - 02:35 AM


Also would the valve shims be the same as kawasaki ones, as my local yamaha dealer doesn't have them in stock.


  • jayh300

Posted December 07, 2009 - 08:11 AM


welcome fellow gg owner....

there is tons of info in that link on those bikes, including a link to a manual...

not sure if the kawi shims are the same, but the honda is...

Make sure you read the one about the threads on the filter cover...

Edited by jhendr3702, December 07, 2009 - 08:30 AM.

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  • tech24

Posted December 07, 2009 - 08:16 AM


You can always get one of these kits and be done with it for ever. Its a more expensive than buying individual shims but you'll be set for life.


On the oil and metal I would just get it in running condition and see how she does unless you wanna go ahead and do a top end

  • grayracer513

Posted December 07, 2009 - 10:16 AM


If you reshim the valves only .05mm or so to bring them into spec, then run the bike 2-3 hours and reinspect the clearances. If they have tightened further, the valves have worn throught their hard coating and need replacement. If they look OK, go another 2-3 hours and check again.

Regarding the metal in the filter. Is this the first time you have had the filter out of this bike? It could simply be that no one has refreshed the filter in the last several changes, and the normal amount of metal has accumulated in a larger quantity due to the that neglect. The filter should be serviced each time you change oil.

The KXF450 shims should be the same 9.48mm diameter shims.

  • 426fnube

Posted December 08, 2009 - 03:47 PM


i have the same issue have you figured it out
mine is an 02 just bought it

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