Motorcycle stalling when accelerating

Hello,

i'm looking for ideas on on problem :

on a kz1000 ltd 77 stock with 4in1 mac air box and k&n air filter.
vm26ss with 15 - 110 jets and synchro done.

The motorcycle stall on acceleration.
I know it is the carbs because with other carbs i don't have this trouble.
Do you have an idea ?

I'm a carb guy, so the first thing I'd do is a full teardown, soak the bodies and hard parts in carb dip, then reassemble with all new O-rings and float bowl gaskets.  Blow compressed air through all the passages, and use carb spray, watching where it comes out, to make sure all the internal passages are open.  Your 15/110 should be fine.  

Doing this is no guarantee that the problem will go away, but you can eliminate the carbs as the cause.  And fresh clean carbs with all new O-rings, is never a bad thing.

That's i will do again tomorrow.
Today i tried and i haven't the problem when the choke is on ...

Fox wrote:

That's i will do again tomorrow.
Today i tried and i haven't the problem when the choke is on ...

The choke is an enrichener so if the problem improves when it is on it indicates a lack of fuel off idle so it is very likely you have one or more blocked pilot jets.

The fault was a cracked tube of the synchro tool.

Old brittle and cracked carb boots are often trouble maker if the engine running lean or idle to high.