Intermittant Cutting out of Engine

[bam347]

I have a 81 XS11 that I have had for about 2 years now, the engine was rebuilt before i got it and didnt run correctly, I found the Cams to be out of time. I fixed it this past winter and just started riding the bike a few weeks ago and it was running GREAT. This past weekend i road it and I got on it hard for the first time. When i slowed down to a normal pace again(55mph) the bike was cutting out really bad. It felt like it was running on 2 cyclinders. When i would roll on the throttle it would get worse, untill i hit about 3/4 throttle. then it would clear up and run perfect untill i let off, and back to cutting out. All on or all off the trottle the bike would run fine. Anything from just off idle to about 3/4 throttle at any speed the bike would cut out. I took the bike home and let it cool off and it ran fine. I put another 120 miles on it that day when it started doing it again. I stopped let the bike cool down, and it continued to do it for about 10 minutes, then cleared up and ran PERFECT. I am not sure if my problem is in my Crabaration or Ignition. Any help would be GREATLY Appreciated.

[bam347]

Oh, and i had the carbs rebuilt last year, but i dont know if it trust the work of the shop because they missed the fact that the cams were outta time

[skids]

I think the crabaration is fine. Makke sure that the tank is not vacuum locking. The breather cap must function or the engine will fuel starve. Do not upen the tank and do 60 mph or you could be doused with gas, BUT you might close a length of wire in the cap to pry the seal open just enough to test that theory. Alternatively, you could wrap your lips around the breather nipple of the cap and physically test it, but that is just plain nasty (Don't ask how I know that).

Theory #2. If the problem occurs only at a narrow band of rpms, try switching to prime and see what happens. If the problem instantly vanishes, you might check your exhaust system for leaks. I know that sound bizzare, but bad exhausts can cause vacuum pressure to disappear which can make the vacuum-operated system (petcock for standard or octo for the special) to fail.

[pggg]

Well a sticky slide can cause those dramas, easing back from full throttle and the motor immediately starts misbehaving(running on 3 cylinders only) but runs fine when back on the gas. The stuck open slide floods the combustion chamber at low revs - the slide eventually drops down again sooner or later and she runs perfect again... until next time...

[oseaghdha]

Almost sounds like its running out of gas rather than the crabarators. Like skids said check the tank vent, or the petcocks may be plugged a bit. Heavy blasts empties the bowls, letting it sit allows them to refill.

[John]

Sounds like it could be the pick up coil wires also.

[mitch]

Pick up wires

Check this link out
http://www.xs11.com/forum/showthread...=&threadid=543
hope this helps
Doug