Main Jet Needle Question

[Colorado CJ]

One thing that I did see that wasn't exactly right with the carbs is that the emulsion tubes (#40 in the previous drawing) were a little ate away where the main jet screws into them. The main jets still screwed in tightly, so I didn't think they would be a problem.

Could this be the problem with lean running? I wouldn't think that they would since the main jets seat against a washer when they are screwed in.

[srsupertrap]

I can't see a vacuum leak anywhere (just replaced all the boots and o-rings with brand new OEM parts). The throttle also returns very strongly when I let go of it and I made sure the throttle linkage was not hitting the boot clamps (saw that one when reinstalling the carbs)

I would agree with the gross statement. Definitively rule out the possibilities though. Instead of stating you can't see a vacuum leak I would suggest after a short ride and it's idling @1800 rpm place a fan in front of the motor. Next spray WD-40 on all the places were it might be sucking additional air. If the idle drops . . . .

PS: You stated it won't idle any lower than 1800 rpm. Is this true even after the initial 3-4 minute warm up?

[Colorado CJ]

Will do. The idle doesn't drop after it warms up. The idle does go lower once it is under load, i.e. I can putt around in first gear at about 1000 r.p.m. without it dieing.

I'll check again for vacuum leaks, but I don't think there are any.

[Colorado CJ]

I changed the needles over (did the washer swap) and the bike seems to be running much smoother and has alot more power now. I drove it a short distance and checked out the plugs. The engine doesn't seem to be running rich at all, the plugs look just about right.

I'll do a longer ride today and look at the plugs again to be sure (if it stops raining).

This really didn't solve the idling problem, although I can now turn down the idle to around 1500. I have a new slide coming for #3 carb (the slide out of #3 is much longer than the rest of the carbs, so the needle sits much lower). I think this will solve the idle problem as I think #3 is still running lean, making for a faster idle. I rechecked all boots and none have any vacuum leaks that I can see. All boots are in good shape and are very tight to the carbs.

I think the washer swap on the needles is the thing to do here at higher elevations (~5000 ft. and above) makes the engine run much nicer/smoother!