Lost air mixture screw Keihin carb.

[bleeds]

Lost air mixture screw Keihin PE40B 37MM

Man I have no idea how this happened, but I uncovered my bike this morn and decided to warm her up a bit and go for a tiny ride. I made an air adjustment, (Side screw next to idle screw, near the airbox end) and took my very tiny ride. When I got back, I noticed the dang screw was missing. Spring and all! How on earth do I replace this part. B*keB*ndits call it a Set Screw in my parts scematic. Does this screw have measurement like a main jet or slow jet? Can I just buy a replacement screw of the same length and thread and be ok?
Bleeds
ANyone know where to get these.. ?
1982 Honda CR250R .50 over
ALSO what are the little numbers etched into the side of the carb near the bowl half?

 

[nickyd]

it happens - buy it from a dealer or online - I think its got a unique shape with a needle point - I can't exactly remember - at any rate, dab some low strength loctite on there in the future - and don't back it out more than a couple turns - if you need to in order to get the bike running then you need to change your jetting. As for the piston, shop any of those online places and they should be able to get you the piston.

 

[bleeds]

Hey nickyd thanks for the info. I have found a wealth of knowledge about this bike this eve..It is actually a PE40B 37MM KeiHin. It appears as if the screw from an 81-83 will interchange in this. same part. I was hoping to find something for a few bucks from someone here.. but oh well. I will have to order it from BB for 17.00 not alot I know.. but just sucks!! LOL thanks again you are one that nearly always replies..thanks!!
Bleeds

 

[mtk]

You shouldn't need loctite. There is a spring behind the screw to hold it in place and you'll need to order it as well.

 

[nickyd]

You shouldn't need loctite. There is a spring behind the screw to hold it in place and you'll need to order it as well.

i agree...however if it fell out once.....

 

[mtk]

Putting Loctite on it is going to create more problems than it solves.

That screw is adjusted constantly, it isn't a "set it and forget it" item. It doesn't need Loctite on it. The spring tension will keep it from falling out. At least it does on every other dirtbike in the world.

 

[soulmate33]

Putting Loctite on it is going to create more problems than it solves.

That screw is adjusted constantly, it isn't a "set it and forget it" item. It doesn't need Loctite on it. The spring tension will keep it from falling out. At least it does on every other dirtbike in the world.

I agree.....and if the spring isn't holding it, it could mean that you are backing out the screw too much to maintain a good air/fuel mixture and need to go leaner on the pilot.

 

[Morvo]

What if you wrap a small amount of ptfe tape around the threads before you install it?

 

[mtk]

Again, why?

The folks who designed the carb were well aware of its operating environment and they saw no need for thread locking agents, teflon tape, or anything else. Their design has proven to work just fine in literally hundreds of thousands of cases. Put it back the way they intended and it will work fine. If it doesn't then something else is wrong. Slopping goop on it isn't the solution, nor is wrapping it with tape best left for the plumber.