I have a couple of Roadstar bikes and recently my 2005 has been giving me problems. Initially the fuel was flowing out of the exhaust but that seems to have cleared-up. Now, however, I'm running into problems with idle when I try to turn the choke off and giving it throttle kills the motor. It will run with the choke on but when it reaches operating temperature shutting the choke off will kill the engine. Any attempt to give it throttle will stall the motor.

I've read through the posts to see if I could find a fix but none of the ones I found seem to have the same symptoms. I will add the bike sits for long periods as I have a bad back from numerous bike accidents so I have a feeling that might be a contributing factor. I was going to remove the carb and clean it but wanted to post this and see if there's any advice before I tear into it.

Many thanks in advance!

If the bike runs OK with the choke "On" after reaching operating temps (about 5 minutes running time using the choke) I would start checking for an air leak at the intake to head connection also at the carb to intake connection. If the AIS is still on the bike check the vacuum hose on the top of the intake manifold for cracks or splits. If the AIS is no longer on the bike that nipple will be capped with a rubber cap. Make sure the cap is still there and no cracks or splits in the rubber, these are all very common places to find an air leak that would give the issue you have described.

BTW

Thank you so much for the fast reply and I'll check it out when I get back home. I forgot to mention the bike is bone stock except for Vance & Hines full exhaust. The only "problem" I've had with it is the backfire / exhaust popping and thought that was just because of the exhaust. In any event I'm in California now dealing with the wildfires but will check it when I'm back in Arizona and report back.

Thank you again!

Backfire on decell is also an indication of an air leak. Backfire from exhaust can also be a exhaust leak. Not uncommon to leak at the exhaust head connection or at a clamped joint on the exhaust system connection.

All of what Dave has mentioned, plus, make sure your idle on a hot motor is set pretty close to 900rpms. I'd be looking for an air leak, also. The intake manifold to head flanges are often suspect. After 13 years, it really never hurts to remove the manifold, surface the flanges, and reinstall it. As dave mentioned, you may find the manifold in such bad shape replacing becomes a viable option. Even with a new manifold, take the time to surface the flanges, before installing it. Yamaha uses orings and grease on the flange surface to allow it to slip and slide and seal when installing. Many here, use the blue high temp non-hardening sealer like Hylomar. Permatex makes one called Permashield. Don't use a silicon type sealer that can harden. If you use the sealer, instead of grease, just use it on the flange outside of the orings.


If you end up digging in that deep, you may as well replace the needle and seat(float valve) on the carb, also. Avoid being ham handed, and messing with the float If you do it. If you regularly use something like MMO or Seafoam in your gas, the inside of the carb will stay in good shape, as far as clean.