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As I said, almost always this is caused by wear in the carb body and the spindles. It makes the butterflies stick open and gradually close. Just wiggle the spindles to see how much play there is. Obviously this may not be your problem, but it usually is. Nothing else except sticking dashpots has quite such a profound effect.
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Idle does not stay constant, why?
- Thread starter AUSMHLY
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Yesterday I checked my HD8s for these issues. Coming off the highway, my car will idle at 1500 and over a few minutes, settle back below 1000.
After ruling out sticking pistons or needles, am inclined to agree with your diagnosis.
On the rear carb, the butterfly must be slightly out of alignment because I can push in the closed direction on the operating lever and it will seat properly and idle at 750. There are no air leaks in the shafts because the carbs were rebuilt before I bought them.
Sounds like a bind in there somewhere. Alignment is automatic as the screw goes in only one place...Loosen the linkage that connects he carbs together and see if it still binds. Also, the carb throttle shafts have a Teflon type of bearing surface and that could be an issue....If it's not obvious, just pull that carb and see what's going on....is the return spring there..and working? Also, if someone put the connecting link on and somehow got some sideways force when tightening it could cause a bind in the butterfly. Good Luck!, Lee