mikuni vm38 issue

I have a set of vm's on my 1978 xs650, its been bored 2 over, uni filters, free flowing exhaust. been riding all summer no issues, then a couple weeks ago while i was riding it cut out. While i was in gear and rolling the engine would kind of run at idle speed but when i would open the throttle nothing would happen, and when i pulled in the clutch it would cut out. let it sit for like ten minutes it would start again.When i first put the carbs on my bike i had to raise the needle to get it tuned in, ran fine for months, then this happened. i dropped the needle down to original position, and it was running fine the original issue of why i had to raise the needle wasnt happening, and this flooding of the carbs or whatever it is that cuts of the bike wasnt happening until yesterday. i tried leaning it out some more but it doest run right and i dont want to run it too lean, even if that is even the problem. please help. thanks

Have you read the carb guide? www.amckayltd.com/carbguide.pdf It tells you all about carbs. It could be as simple as crap in your tank plugged up some of the passages in the carbs.
This crap in the gas can come from a rusty tank, bad gas, crap from the gas stations tanks.
A tear down, clean and inspection of the carbs is needed.
Leo

So - why have you ruled out electrics ?

I don't think they've ruled out the electrics, Pigford, it is just we are all very much aware that we should check the connections first. Sounds like it could be something as simple as dirt in the carb or an earthing problem (loose wire somewhere).

Analf

what electronic circuit would cause it to bog out and then wait 5-10 minutes before restarting? could the coils be overheating? they are a new coils as of last year. i cleaned out the carbs last night and it hasnt stumbled or stalled out. hopefully that did the trick. thanks for the input.

Could be coils, could be a plugged vent in the gas cap, could be a partial blockage of a fuel line, petcock, or filter. could be a really tight valve, could be.............
Check, confirm, eliminate, til you find the problem.