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CB77-E 1053411 throttle return to idle

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Jim Stuart Member
Posts: 41
Joined: Mon Nov 26, 2007 4:03 pm

CB77-E 1053411 throttle return to idle

Post by Jim Stuart » Wed May 14, 2008 1:35 pm

The question is: I think I have finally got the timing down pretty good. The right side is not quite as hot as the left. But---when I goose the throttle it takes a long time (10 seconds) to come back down to idle. Is this normal. Air screws are about 1.5 turns out which makes it idle well.



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davomoto Member
Posts: 2508
Joined: Sat Nov 18, 2006 7:36 pm
Location: Marin County CA

Post by davomoto » Wed May 14, 2008 3:12 pm

Jim, not normal. Are the slides returning to stops right away? You can remove air cleaner tubes, and visually watch them. if not, you'll need to lube cables, and throttle tube, als remove slides and make sure they move freely in carbs. If they do return, you probably have an intake leak, or tight intake valves, both of which are not good for you engine. Spry carb cleaner around mounting areas and see if engine revs up, and check and adjust valves.


jesmed Member
Posts: 79
Joined: Tue Jun 14, 2005 4:53 pm
Location: Cambridge, MA

Post by jesmed » Thu May 15, 2008 8:50 pm

I had major, major trouble fixing a similar problem on mine. As davomoto says, not normal. (For a while I was able to compensate with an idle air screw adjustment, but eventually the problem got too bad and even closing the idle air screws fully wouldn't compensate enough). I checked all possible culprits thoroughly, including air leaks, valve adjustment, timing advance, etc, etc. Eventually the only possible culprit I couldn't rule out was an internal air leak around the slides. I even tried new slides, with no improvement. I figured maybe the carb bodies were warped/worn too far. Eventually I had to swap out both carbs after checking EVERY other possibility. Finally, on my THIRD set of carbs, the problem went away. I hope you don't have to go that far. If you're lucky you have a "simple" air leak around a carb mounting flange or phenolic spacer.

deaddog Member
Posts: 165
Joined: Fri Feb 23, 2007 9:33 pm
Location: South Florida

Post by deaddog » Fri May 16, 2008 12:37 pm

Please try this before you do anything else:
Loosen the two nuts holding carb. on and just barely tighten them just past finger tight. Nine out of ten times that is the problem.

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