Running great on three cyclinders, Help!!!

[Don-lo]

You are correct, 29mm smoothbores do not have a vacuum takeoff on #3 carb for the petcock. Those 2 vents need to be open.

Is the pipe on #4 heating up when you run it?

Have you tried swapping parts from 3 to another carb? Separating the carbs again is ridiculous. You can flush out those passages with gumout and air and verify they are flowing. Concentrate on the precision surfaces, using fine copper wire strands to verify they are open.

Odd things to look for:

- Different slide cutout number
- Different needle number
- Different/internally corroded needle jet tube
- Bad choke plunger
- missing plug in carb body
- damaged fuel screw/port

If you see nothing, swap all the components in the bowls, #3 to #4, see what happens

also, swap #2 and #3 plug wires, please

[slip]

You are correct, 29mm smoothbores do not have a vacuum takeoff on #3 carb for the petcock. Those 2 vents need to be open.

Is the pipe on #4 heating up when you run it?

Have you tried swapping parts from 3 to another carb? Separating the carbs again is ridiculous. You can flush out those passages with gumout and air and verify they are flowing. Concentrate on the precision surfaces, using fine copper wire strands to verify they are open.

Odd things to look for:

- Different slide cutout number
- Different needle number
- Different/internally corroded needle jet tube
- Bad choke plunger
- missing plug in carb body
- damaged fuel screw/port

If you see nothing, swap all the components in the bowls, #3 to #4, see what happens

also, swap #2 and #3 plug wires, please

Great suggestions, I will do this when I get home. I feel like I am close, so hopefully I am.

[slip]

Well I am a bit embarrassed. The problem with #4 was that the main jet was completely clogged. And the number 3 float height was off by about 10mm! The bike is running like a scalded cat now. Only thing is I could not fully appreciate it without any front brakes, can't wait for that caliper boot to get here. No calipers on the front! It is finally running decent!! It is not perfect, as number 3 is still running just a tad rich. But nothing some fine tuning can't fix. I am still perplexed with 3 though, as I thought for sure the float height would have cured it. Can I adjust this out with the pilot screw???? Thanks for all of the help here, and being most patient with some of the dumb questions.