TOPIC:

Here is a video of what is going on with my carbs. When the bike is fully warmed up the RPMs fall slowly sometimes. Other times they drop fast and it almost stalls. Doesn't misbehave at all when its cold.



At first I thought it was my cables binding up but when I manipulate it right at the carbs without touching the handle it still does it.

If I rev the throttle sharply and chop it off, the revs drop quick to the point it will sometimes stall. If I do it easy the revs will hang. I am at a loss here.

This thing just developed three problems in the space of a few weeks. Leaking tach seal, a charging problem, and now this carb crap. I am so glad I bought the Busa so at least I have something reliable to ride while this thing continues to misbehave.

What you're describing happens when the carbs are set up with the throttle open to the point where the main jet circuit is just coming on and the transition circuit is no longer supplying enough fuel to keep the engine running. This usually happens when the idle/transition circuit is partially blocked and causes you to open the throttle to this point I described to get the bike to idle. So I'm suggesting that your idle circuit is partially blocked and you have the throttle too far open at idle. What's happening is as you shut the throttle, there's fuel dribbling through the main jet causing the engine to slowly ramp down rather than drop to idle like it should.

Been there ! Mentioned this a while ago but can't find that thread. My issue was identical. Found I had turned the syn'c adjusting screws down a bit too far fully compressing the spring inside the link. Too tight on the ball-ends. Backed them off a bit, re-sync'd and that was the end of that. Confirm there is a slight bit of slack in the Throttle-cables. Hard to tell from the video. Let us know after you've checked this. There is another check you make but not going to mess with that at this time.

Too lean at Idle which is essentially what Kawboy and Scotch have both described but for different reasons.

Before I tear them apart again, maybe I will try backing off each sync screws evenly. I broke my damned sync gauge so I have no way to reset it. Pretty sure there is enough slack in my cables but I will double check that as well. In fact, I'll unhook them to eliminate them completely.

ledkz1300 wrote: <.... maybe I will try backing off each sync screws evenly.

That will certainly clarify and hopefully resolve the problem. And as it can be done on the bike with only the tank off, it's the easiest thing to check first. Although the outside of the carbs look clean,also check to ensure there's no gummy/sticky lube residue on/in the ball ends. I don't like running this linkage dry but I can see the potential for old oil.grease causing some sticking issues. Removing the three link-arms is best done at the bench and may require you removing or at least loosening the mounting bar (on the bottom). You just have to "hold your tongue just right". If you go to that extent and old lube is in question - disassemble the link-rods, spring and pins, wash thoroughly and reassemble dry. I lube the ball ends when reassembled and connected. I use a long neck machinists oiler with a precision tip that can apply one drop of a high quality machine oil to the 6 ball-ends. That in my opinion is all the lube they need.

Sync as soon as you can !

Keep us in the loop.