1995 Yamaha YZF 750 R carburetors contaminated from sitting clean them all out but the bike won't idle unless the choke is pulled out a bit then it will run but backfires when you let off the throttle, starts and runs ok any ideas?

SOURCE: 2005 yamaha yzf 250-unstable idle

I had the same problem, Turns out that my shims were finished, replace the chims and check clearences.

SOURCE: engine cuts out as you accelerrate when in nuetral.

You might have a coil problem or you might need a sparkplug cupor you need to synchronize your carbs.get your valves check also.

SOURCE: Yr 2000 thundercat, won't idle unless choke fully on

First thing I would try is some sea foam, you can get it pretty much at any auto parts store...put it in the tank per instructions on the bottle, if the carbs are gummed/dirty... seafoam is you best hope at getting them clean without pulling them.

If sea foam doesnt work, you'll have to yank the carbs, but before you do... pull the tank, set it backwards where the seat was, get about a two foot fuel line (air line works just fine) run it ti the tank and start the bike, take a can of starting fluid (WD 40 works too but stinks when it starts to burn off afterwards) and spray around the base of the outside of the carbs where the boots connect it to the intake, if the engibe revs, you have a leak...cracked boot probably.

If no leaks are detected... then yank the carbs, pull the bowl covers and start cleaning....also, while you have them off pull the slide covers off and check the diaphrams on the needle for rips or cracks as well.

Check/clean.. put everything back together... if it still isnt running right then I have no other suggestions... certainly sounds like an air/fuel problem... if were anything else choking it wouldn't make it better.

SOURCE: I am having running problems with my 2004 Yamaha

sounds like a partially plugged pilot or idle jet in the carb, either that or a vac leak. roadstars are known for intake leaks around the flange and make sure that the clamp at the back of the carb is fully tightend to the stop. roadstarclinic.com is a good source for information!

SOURCE: rebuilt all four carbs cleaned and replace needle

With Mikuni carbs, the idle circuits affect engine performance up to 3000 rpm under light loads. If the idle circuits are restricted (by fuel gum, rust dust from the tank or dirty fuel, the results will be 1) the engine will run with "choke" on. 2) poor or no throttle response below 3000rpm,3) back firing and missing on the effected cylinder(s). Cure is to blow out the idle circuits and idle screw adjustment jets with several applications of carb cleaner and compressed air. Failing that, strip the carbs.