2000 stainless valves in 2001 head

3 replies to this topic
  • bighep

Posted August 30, 2016 - 04:44 AM


I just rebuilt my 2001 yz426f with valves and springs from the 2000. Question is should i now use the clearances from the 2000 which are a little greater?

  • grayracer513

Posted August 30, 2016 - 09:54 AM


Yes, you should.

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  • bighep

Posted August 30, 2016 - 09:56 AM


Thanks. .. may explain why its not running quite right through mid range

  • bighep

Posted September 06, 2016 - 06:23 AM


The bike is running rich after the switch to the stainless valves and new weisco piston std compression. Dont know if this is coincidence or maybe it was rich all along. I have all 2001 stock jetting and with the needle all the way down and the screw at 1 3/4 out it is running decent but not 100%. Should i go to the next leaner needle size or do a smaller main jet, it starts fine and wot seems strong, it just the mid that seems to be off. Im riding in northern mi at about 1200 ft elev. Any insight would be appreciated.

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