WR426 auto-decomp - freeze plug, decompression plug and a few Q's

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  • Pooley

Posted August 11, 2014 - 12:17 PM


So, after searching around on TT, it appears that there are 2 methods of sealing off the decompression shaft when converting to the auto-decompression exhaust cam.  


The 2 methods are to get a "freeze plug" from an auto parts store, or to buy a decompression plug like this one in the TT store https://www.thumpert...=search_results .  This plug does not show that it fits the 2001 WR/YZ426, but does it?  Would the #15 plug from a 2003 WR450 fit the same hole? https://www.thumpert...003&model=28790


Regardless of which method is used, would I need to have the oil seal in place?  #15 on the diagram https://www.thumpert...001&model=28895

  • Just read on ThumperFAQ (http://www.thumperfaq.com/) and it sounds like the oil seal is not necessary.  Would still like confirmation.

If I ever sell the bike (unlikely) and the new owner wants to go back to manual decompression for some reason, can freeze plugs be removed? I have never heard of them until today.  Is there any worry about the freeze plug popping out.  That scares me to be honest, and I'd rather spend $20 to have something that physically locks in place, vs a $1 cheap fix.


Lastly, which is the preferred cam to purchase (keeping WR timing)...Hotcams or OEM exhaust cam from a WR450, and if there is a preferred year for the OEM cam.

  • ThumperFAQ stated "The 450F cam gear has a different tooth pitch, even though the tooth count is the same.  the new cam will work for a while, but the chain and gear will ahve accelerated wear."  Sounds like Hotcams is the answer.



Edited by Pooley, August 11, 2014 - 02:01 PM.


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