should i buy new carbs

[peanuts]

I had my 78 carbs dipped. all parts are new. the bike runs great, but when i shut it off the left carb overflows. Floats are set at 22/24. I know i need new petcocks the old ones are vacuum and wont close all the way, so there is always fuel to the float bowl.
Is the needle jet (pin) not seating all the way.

 

[yamaman]

All parts new? New floats? New needle and seat (aka float valve) Floats adjusted properly? Floats not floating? What carbs? More questions coming up, feel free to answer them before they are asked. Cheers

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[gschob]

The float could be saturated. Meaning that there is a crack in the float and it is partly filling up with fuel and not floating. I've had that happen to me twice.

 

[5twins]

Are you made of money? Then sure, buy new carbs, they're only $400-$600. Get me a set while you're at it too, lol.

There are good new parts and bad new parts. The float valve assemblies in most of the aftermarket rebuild kits are of questionable quality. My local dealer told me he won't even use them anymore he's had so many "new" bad ones.

 

[DogBunny]

"Is the needle jet (pin) not seating all the way. "

Very likely, and the probable reason is that you say "all parts are new" which probably means you used a re-build kit and the crappy float valve that came with it.
The float valves in most BS38 kits are crap. Take a look at the needle and the seat under a magnifying glass, and you will see that they are poorly made and make a poor seal. I have never tried one that didn't leak. You should only use genuine Mikuni float valves with the BS38s. Put your old Mikuni valves back in, or order some new ones if you already discarded them.

 

[gggGary]

Just a heads up, or maybe it's a question, "dipped" is not = to "cleaned". No matter how good your workmanship or quality of parts used if the whole fuel system isn't cleaned or replaced crap will constantly show up and fuggle the carbs. Reusing fuel lines a common cause of leaky floats. the line sheds little chunks that lodge in the seat. Old brass floats often have fine hairline stress cracks and leak. Hint: Drain gas through your float bowls into a clean white container, what do you see? (cut up a quart oil bottle the long way to fit under carbs)

 

[peanuts]

I took the new float and sat it in a pot of water..then I heated the water up. I did not see any bubbles. I think its the needle..I will check it with a magnifying glass to see if the seat it rough...Thanks..I'm learning every day..

 

[gschob]

An old trick that will save you some time to test if they are still leaking or not. Is to lightly blow into the fuel line port. With each carb up right. Then flip them upside down and do it again. You should be able to blow trough it when it's upright, but not once it is upside down. Flipping it upside down simulates the floats being in the up position. Once you get them to pass that test then you can put them back on the bike and test it with gas.