Jump to content

YZ250 mixture screw seepage

Recommended Posts

So this is what the area around the mixture screw looks like after spending a day in the sand. Is this normal? I have tried to unscrew the screw to check/replace the o-ring that is supposed to be there, but the screw wont come off. It is like there would be some circlip or something on the other side holding the screw in place, but according to schematics there should be a spring, a washer and the o-ring. Can't see a reason for it not coming off. It adjusts idle mixture fine, though, and there is no obvious air leak.

gunk.jpg

Edited by kilikoli

Share this post


Link to post
Share on other sites

I ordered a new air screw, I think it came with an O ring. Mine felt the same way because previous owner had used a flat blade screwdriver that was too wide for the hole and buggered the last threads. I cleaned mine good, screwed it all the way in and took a nice little pic to clean the threads as good as I could. it came out OK so I picked the threads again as good as I could and the new one when in and has been fine.

 

  • Like 1

Share this post


Link to post
Share on other sites

Mine had the head stripped, same flat blade screw-driver damage. I had to drill it and use an easy-out to extract it. I bought a new screw kit and a tap to chase the threads. All good now.

  • Like 1

Share this post


Link to post
Share on other sites

The topmost threads were damaged here, too. I carefully drilled those couple of threads away and the screw came off after that. The o-ring looks a bit special, so I just cleaned everything (the hole, too) and put it back thogether. Seems like that helped, maybe the o-ring was not properly seated. Guess I'll try teflon tape on the screw if it starts seeping again.

Thank you, this would have taken a while to figure out by myself.

  • Like 1

Share this post


Link to post
Share on other sites

FYI, the spring goes on the screw then a flat washer and the o-ring last. I think the flat washer keeps the spring from tearing up the o-ring.

  • Like 2

Share this post


Link to post
Share on other sites
5 hours ago, Ron W said:

FYI, the spring goes on the screw then a flat washer and the o-ring last. I think the flat washer keeps the spring from tearing up the o-ring.

Exactly!

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

Reply with:


×