Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0

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

1 post in this topic

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.thumpertalk.com/shop/cart.php?search=decompression+plug&m=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.thumpertalk.com/shop/oem.php?partcategory=871319&manufacturer=7&category=5&year=2003&model=28790


Regardless of which method is used, would I need to have the oil seal in place?  #15 on the diagram https://www.thumpertalk.com/shop/oem.php?partcategory=897306&manufacturer=7&category=5&year=2001&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

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  
Followers 0