After rebuilding my tr34 engine im having problems getting it to run properly it will start with the choke out and warm up when i push the choke in it slows to a idle the problem starts once i try to rev it i have followed the instructions for setting up that i obtained from off-road .coms ride -net web page for the mikuni carb but i dont really know which screws are which i have a large thumb screw at the base of the carb which i assume is the idle air screw or pilot air screw i dont seem to have a throttle stop screw or cant see one on the side of the carb.

When i open the throttle it seems to choke the engine regardless of where the thumb screw is set believe me when i say i have tried it from fully closed to fully open in 1/4 of a turn increments to no avail apart from my left foot being black and blue from trying nearly all bl---y day any help will be greatly appreciated as im at my wits end and sick of hearing it go buuuurr and die out.

sorry I know basically NOTHING that can help you big wheeler...but I;m sure you'll get some good advice soon though..

but one thing I did wonder, is ..on the main jet there is a rubber O ring???...I think most carbs have that??...apparently if that is perished/damaged, it can really mess up the performance....might be another thing you can check??...good luck!!

How about some piccies of the bike??...would love to see them!

The big screw is idle speed.

It's just a tapered needle that raises the slide when you turn it in.

The smaller one is mixture.

Check the float level and make sure the needle is free in the seat.

Beware rubber-tipped needles. Gasolone formulas are changing all the time and causing havoc with rubber (and paint!).