another 80 xs 1100 std. carb problem

[SFSPECBIKER79]

just inhereited another 80 xs 1100 std. with carb troubles. i hook up fuel tank. turn on the fuel. the bowls fill, start the engine then black smoke starts rolling out back of tailpipes,and it is loading up from 1000 to 3000 rpm. after 3000 it rockets to 10000 to 10500. so i turn off gas to carbs run it for a minute till all the gas line has cleared, then it is fine 1000 to 10500rpms and idles sweet, so the floats are set to high, i think. the carbs are clean and just put in new float needle seats and needle. plus new plastic floats, all new jets what do i need to do. to lean it down on the bottom end. turned the engine off when it started running perfect. and pulled the bowls off carbs, they had enough fuel in them to cover the hole that the brass pipe slides into. would this be the proper level for good performce. sorta stuck what to do change float level or jets? the main jet is 137 pilot is 45

[DGXSER]

Hmmm...Well..depending on what type of carbs you have, the mains could be oversized by alot. The 80 model year was the switchover so some had the older style carbs and some had newer. Best thing is to see if it has the crossover to feed the pilot from the main jet and a plug in the pilot jet bottom. If it does, those 137 should be ok. If it does not, those 137 should be more like 110-120s.

That will also change the float bowl settings. The older style used 25.5 mm IIRC, and the newer use 23.5 mm.

What you describe sounds like one of two things IMHO, either you have it right with the float height, or your new float valves are still not seating and sealing properly.

[SFSPECBIKER79]

re carbs

it has no plug over the pilot. i dont know about a crossover. and like i said it runs great after all the gas in the lines burns down out of them. they seem to be holding the fuel in the bowels. its not leaking out of the throats or running into the crankcase. i have some 120s i could try. i think the floats are set ok.

[DGXSER]

If you pull the main jet out and then slide hte needle jet/emulsion tube out, you should be bale to see the hole that runs over to the pilot jet. I'm pretty sure you should also be able to see the threading where the screw/plug woudl go in the top of the pilot jet hole which I do not think the newer model has the threads there.

From what you described, I would put the 120s in and verify the float heights.

[SFSPECBIKER79]

re carbs

i'm pretty sure these are the newer 80 carbs the have the plugs in the mixture screw holes. the plugs have been removed and the needles are not broken off. so you think the jets are to large causeing it to be rich in the lower rpm range. thats what i was thinking to. i have lowered the floats to stop the fuel flow to give lower fuel level in bowels. i dont think i can go any lower. i'll try the 120s tommorow see what happens, thanks alot

[tarzan]

If your problem is below 3000 rpm then its either floats like you thought or you may have a problem with the pilot circuit.
Also another thought,do you have pods or airbox?Maybe restricted air jets?

[petejw]

If the problem is below 3000rpm,
its more than likely your pilot circiut,
in your signature it states that the bike is stock,
id be putting 42 pilots back in and adjust your mixture
screws accordingly and see how you go from there.

[DGXSER]

OOPS Missed the enlarged pilot jet as well. At stock the pilot should be 42.5.

Yes, the main is supposed to only effect the higher RPMs, when it is properly sized. But at 137 instead of 110-120, I would think the carb would still draw through it even at lower RPM. IMHO, the rpm ranges stated for each area of the carb are where it has the MOST effect, not the only place it has effect.

Reality is, those 137s need to be changed out, and yes, he probably will want the 42.5 instead of the 45s. Recheck float level just to be sure, and try it again.

[xs11widowmaker]

What kind of pilot jets are you using? I was told that if you dont have the BS jets you will run rich nomatter what. I just changed yesterday and it made a world of differance. I use to foul plugs in a matter of miles and with the new jets im kinda lean now.