Hi Guys,Mikuni carb. Fuel flows until I put the float chamber on. Then fuel will not flow. At all.  Cheap carb from Ebay engine starts with 1 kick and immediately revs to 8000 rpm with choke. Turn off choke and it dies. NO CHOKE, DOES NOT START. Change main needle and set on #2 slot to lessen the richness and same thing.  I would really love to use the Mikuni carb but can’t figure out why the fuel won’t flow with the float chamber attached. No rubbing, needle is not stuck. Fuel flows without chamber and float works when I activate it. Any suggestions?
Ts

With the Mikuni, I would suggest that the float height needs adjusting.

Yep, did that. Tried changing needle and position. Even tried different floats. Thought maybe they were getting hung up on the chamber.Thought maybe the air vent was clogged but air passes through. Putting it back in the ultrasonic today just to make sure. I've cleaned this carb at least 6 times but after reading the posts here, 1 more time won't hurt.

Well look at me! Mr. Smarty pants (me) just re adjusted the float and you were correct!

Next time you give me advice, I will NOT question it!!!

Still need to adjust but it fired up on first kick.

Thanks you.

Ts

Is the float upside down if you had to bend the tab a lot from what is reasonable to get the result.

Okay. Carb issue fixed but, only runs with choke on so I'm thinking air leak. When I first got it runnining after rebuild, I found out the muffler was plugged up. Wound up putting it in the bon fire and now exhaust is good.

But, while it ran with the muffler plugged it was exhausting below the head. Could I have blown the head gasket? If so, would that contribute to it being too lean?

I am pretty sure it's not leaking air around the carb.

Thoughts?

Actually below the cylinder not the head.

Re the bike not running without choke, even though you have cleaned the carb, can you actually see all the way through the pilot jet when holding it in your fingers? You should be able to see through the pilot and main jets.

If the base gasket is blowing, there should be oily deposits in that area. It can be tricky to seal the exhaust into the cylinder, so just make sure that it isn't blowing there.

There is an oily mixture leaking between the cylinder and the crankcase. Would that type of a leak cause the engine to run lean? Regardless, I'll have to replace the gasket because I don't want a leak after all the work I put in. No other apparent leaks. I'll replace the carb gasket while I'm at it also. All jets are clear.

I just hope I don't have to take the engine off the frame to do it.

Yes, it would cause it to run lean, but from what it sounds like, not as lean as you're describing. But it's going to be really hard to diagnose anything correctly without fixing that obvious problem first. Maybe you're base gasket is leaking more than mine was

You don't have to take the engine out of the frame to get the cylinder off. It's pretty easy work. While in there take a good look at the overall cylinder and piston condition. As you'll find the work is fast enough these don't warrant replacing the piston just because you're in that deep - but if there are any signs of damage or scoring, that might be your next step.

While you'll need a new cylinder base gasket, the head gasket can be reused if you anneal it with a propane torch or similar.