'06 WR450 fuel screw help

My bike will not start after sitting for a couple of months so I thought I would replace the pilot jet. As long as I was in there I purchased an MSR fuel screw to replace my stock screw. In the package was just a screw, spring and an oring. Can I assume that the spring goes onto the screw then the oring on the end. It seems to me that there should be a flat washer between the spring and the oring, true? When I pulled the stock screw out there was only a stock brass screw a flat washer,spring and no oring. Looked up the hole with a mirror since the carb is only dangling by the cables and could not see anything up in the hole.

I guess my question is does the stock mixture screw have an oring and another washer between the spring and oring. Should the MSR replacement have a washer between the spring and oring?

Thanks for your help!


Your stock screw had, from bottom to top, a spring, a washer, and an O-ring. The fact that you didn't find the O-ring means that it either fell out, or is still stuck up in the bore.

Your aftermarket screw assembles the same way: screw, spring, washer, O-ring. Don't double up on the O-ring, and don't assemble it without the washer. If necessary, you can remove the float bowl to verify the presence or absence of the old O-ring.

Thanks Grayracer,

That it is kinda what I was thinking. It does not appear with a mirror that the oring or washer is stuck in the hole so I suppose it is possible it fell out when I removed the screw without noticing it. For the new screw I guess I will have to find a washer that will fit. I will check with the dealer where I purchased it and let them know it was not in the kit.

Thanks again for your help!


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