Carbon in head and valves

5 replies to this topic
  • TNT

Posted November 11, 2002 - 04:58 PM


I need a little help !!! I have a 02 WR426F pretty much stock. I went on a long ride (aprox 250mi)the bike ran great got back to the truck and turned it off put it in the truck went home, a couple of days latter I went out to do some maintance replace the plug, clean the filter ect. I went to start the bike to warm the oil to change it, and the bike had no compression. The dealer said that there was a 95% compression loss,the loss was from carbom build up on the valves and head. To fix the problem they would need to machine the valve seats and replace the valves to the sum of $1100,and the only thing the dealer can tell me is wrong, I used too high octane of gas (92 octane ) because a 87 octane will burn hotter and burn off all of the carbon. That can't be the problem please help

  • blue_beast_wins

Posted November 11, 2002 - 07:44 PM


What a load of crap, get the bike back of those incompitant bastards, give us more info on your milage and jetting etc

If you are not confident doing the motor your self, ask some questions, there may be someone here close to you that can help you with it.

  • endurodog

Posted November 11, 2002 - 08:19 PM


I thought I had read here that some bikes may lose compression for a short time. They are hard as hell to get started but once you do the problem corrected it self. Sounded like the decompression release was sticking in these machines. May want to kick hell out of it before forking out the money or tearing into it all the way yourself.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • blue_beast_wins

Posted November 11, 2002 - 08:31 PM


Sounds to me like they have already got the head off.

  • Dodger

Posted November 12, 2002 - 06:25 AM


Egad buddy, go rescue your bike, like NOW!!

A) Theres a very good chance your just experiencing the same temporary compression loss as a lot of other people here on the WR/YZ250-426 boards.

:D If there is a problem, I'll bet the guys on the board here can help you out, and most likely save you a cool grand!!


Dodger :D :)

  • x2smoker

Posted November 12, 2002 - 08:16 AM


I doubt that excessive carbon would cause this. That would mean that one of the valves has so much carbon under it that it cannot shut. I would check the decompression mecnhanism also!

If you are not mechanically inclined enough to properly analyze it, I would highly recomend a secong opinion, from a different mechanic.

It just doesn't sound right. Not saying that the dealer is trying to rip you off, maybe the mechanic isn't familiar enough with the WR mechanics and jumped to the wrong conclusion.


Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.