125 dies when choke is off

[ricky_191]

Hi all. I have a 125 pit bike, kinda a mix of a atomik,orion,ducar engine, with a minkuni carbie with the electrics of the atomik running it all mixed with some new parts..

Anyway , I cleaned out the carbie and jets and put it all back together with the stock setting of one and a half to two turns out on the fuel mixture and it starts and runs when the choke is on and idles a little high.. But when you turn the choke off it will still run good but won't idle.

The throttle is all good and the slider goes from the bottom to fully open. It revs good but there is a slight hesitation when the choke is on but only sometimes.

I tried turning out the idle screw but it doesn't drop rpm and when turning it in it gets higher..

So what could be wrong ?

 

[my67xr]

i would be pulling the carby off and apart.
the idle-1/4-ish throttle is ran off the Pilot jet circuit.

i'd be checking that the Pilot jet is clean through all the ports, centre and side.
also check where the Pilot jet screws into, make sure you can see through into the main bore of the carb.
and the port on the air filter side that supplies the airflow to the pilot too.

i wouldnt be adjusting it with the choke on, it'll make it harder to sertup correct.

 

[ricky_191]

Yeah it's all clean in there. It runs ok but it idles high and not at all when the choke is off :/

 

[ricky_191]

I took the carbie off and looked all through it again and it's clean. So I turned the fuel mix out to the two turns and put it all back together. Adjusted the idle without the choke and it starts and runs so good. No hesitation with throttle and goes good all the way through the revs.

The only thing now is with the choke on , it's revving a little high still but the choke isn't needed to start it. Without the choke the idle is perfect and revs good. Nice throttle response.

So does it matter that the idle is a little high with the choke on or is it meant to be like that ???

 

[zwebx]

its meant to be like that.. i never use the choke anyway.. because all the choke does is block air flow it sucks more fuel from the bowl of the carb and increases rpm

 

[ricky_191]

Awesome then.. It seems to be at a good tune now. The idle screw is about half way out and the fuel mix at two turns out and it has no hesitation at all. The throttle response is amazing All that from a broken bike and an engine that has been out side in the weather for three years.

Now I only need the axle to be able to ride it Should go pretty good.