hi everybody, only my second time on here and still in need of help !! dt125r will start after much kicking run, flat out on choke then cut out. when it does run if you turn the choke off it dies, if you touch the throttle it dies.the carb has been ultrasonical cleaned,new plug and airfilter, fresh fuel and it has a good spark.its doing my head in why wont it START !!!! PS there is asmall white plastic connecter on the right hand side just under the water cooling pipes , should this be connected to anything ?

any help would be greatly appreciated

I am about as far away from being an expert that you can get but a similar(ish) problem on mine was caused by the air mixing screw being fully closed on the carb.