Motorcycle Repair: Fuel starvation KE125, fuel air mixture, fuel starvation

Question
Hello Mr Petruccione,
I'm the proud owner of a Kawasaki KE125 (1980)and its just been rebuilt by me(I'am a motorcycle technition), fuel starvation problems.It runs for 2-3 mins then stops, and if you leave it 5-10mins it will start up again relatively easily(with the choke on and the throttle stop screw fully in,we need to run it obvoiusly first then fine tune its idle).
I think ive checked everything but there might be something else you could think of.
I've cleaned the carb,jets airways etc.
The air filter is ok.
the float height has been set according to the manual.
The needle clip is on the groove specified by the manual.
It has just been fitted with the correct piston (and compression is good).
The float valve and seat are not worn.
The fuel pipe is new (1/4 inch diameter).
The fuel tap has been dissammbled and cleaned.
The fuel tank cap has been dissassmbled and cleaned(no perishing or blockages).
The rotary disc valve and '0'ring are in good condition and correctly fitted.
Crankshaft seals are ok.
The ignition circuit is correctly timed and sparking well.
I cant think what else has been done,and I cant think of anymore faults that could be causing this starvation of fuel.
Thanks for your time, i hope you have any more ideas.
Graham Matthew

Answer
Graham,
 Yes, it's possible you are starving for fuel, you shouldn't have to set the idle that high to start.  Be sure the jet orrifaces are not damaged (if anything was used to "poke" the holes clean they could have done irreputable damage, only solvents and compressed air).  Be sure your floats are not leaking in fuel.  If they are allowed to they'll just sit on bottom and let the bowl overfill.  Start with the fuel/air mixture screw 1 1/2 turns out.  
As for electrical, be sure the plug is gapped correctly and do not overlook the coils.  Check the high and low tension resistance, they can cause this kind of failure.  Also, be sure all electrical connections are tight and clean.  If you have a bad condensor connected to the point set you can get this problem as well.

Good luck,
Mike