rpms hanging up also

The rpms on my xs400j maxim are also going wacky. It will idle and stay at an idle until you start to give it gas and it may stay at high rpms all by itself the linkage has returned, the throttle cable is loose, the butterflies are closed. Yet it tends to stick and doesn't come down until it wants to ??? I cleaned the carbs twice now, bench synced, adjusted idle screws, runs decent, just hangs up, polished the bores and passed the clunk test. When the diaghrams are in place and the carbs are assembled the clunk is more like a slow drop (I assume the vacuum is doing its job at that point). I sprayed some ether around the carbs at idle and did notice a little rise on the one and I tightened the clamp on the intake boot. Would bad bushings on the throttle shaft make this happen ? I did not replace them, I also did not soak the bodies in carb cleaner but used a little cleaner and lots of compressed air to clean the passages.

 

What's the plugs look like? could be throtle shafts if theyre white. Spray starter fluid on the boots coming out of the air box as well. Could be leaking there as well.

Let us know

 

Use a unlit propane tourch to check for vacuum leaks. Turn the gas down low and go over the carb boots slowly and if the idle picks up, you found it. Starting fluid evaporates too quickly to pin point leaks.

 

Thanks, I will try the propane, ran it some more yesterday, I think it has been sitting so long that it seems to get better every time I run it a while, raced it up and down and it seemed to get better as far as smoothness and coming down to low rpm, but the right hand exhaust was definitely glowing red at the end of its workout ? that side id still lean right? what would you adjust, I have been tweaking the idle air screw, It sounds like the timing is just off a bit, is that adjustable with this ignition?

 

Sounds like you should pull the carbs and give them a real good cleaning. You have dryed gas plugging up some of the jets/ports. When your exhaust is red hot like that it may be burning your pistions and valves. I would recommend getting the carbs right before you do anything else or you will be tearing more apart than the carbs. Good luck and lets us know how its going.

 

Timing is fixed unless there's a malfunction. You likely still have a carb issue of some sort.