cm250t custom

[lingeringstin...]

If you've been inside your carb then you've probably already seen everything but one time I had a bike that would start and idle fine but the moment you opened the throttle it would die. Turns out the fecking needle had actually come loose from the slide (little clip thingy failed) and it was just sitting loose down in the main jet regardless of what I did with the throttle.

I don't know which carb you've got but on a lot of them the idle jet and the main jet are at two different levels in the fuel bowl, so the idle may be getting fuel but if the floats are out of order there may not be enough fuel in the bowl to come up to the main jet.

Also some carbs (old Honda designs as I recall) incorporate a little pump mechanism that was supposed to give a wee squirt as you opened the throttle but they were shit and if the pump wasn't working right all you'd get at initial throttle blip was a suction of mostly air and the bike would die.

[vorlon]

so update.
took the carbs off and cleaned them, put back and found the choke cable was no good. ordered a new one. carbs off again and another clean. put back on. took all the fuel out of the tank and replaced with new E5.
engine started but seemd to be on choke all the time. so off again and given a good look. it seems that i bent a tab which is part of the return spring. bent it back and back on again. success and its seems to be running ok.