Post Master General
Join Date: Apr 2012
Location: Bowling Green, VA
I Ride: '09 ZX6R
If the clutch were worn out, it would slip -- that would limit your top speed. Engine revs would go up out of proportion to the change in speed. that's when it's slipping.
if it idles well and runs worse at higher RPM, that's more likely to be related to the state of tune, than the clutch. Typically if the carbs are gummed up that is worst when the bike is running on the lowest speed circuit, as the passages in the carbs are smaller and gum up more (first) there.
If your fuel filter is clogged, the bike would starve for fuel when you place a bigger demand on it. It may be able to flow enough fuel for idle and fall on it's face when you ask for 4X as much, as an example.
Any way you look at it, one of three things is not as it should be. Air, fuel, or spark. If it idles and runs smoothly, odds are fair it's not air or spark.
Is there any rust or debris in the fuel tank, or in the fuel filter?
What is the condition of all of the vacuum lines that are supposed to be connected to the carbs? Do you have a carb balancing tool? Can you synch them?
When was the last time the valve clearances were set? How old are the spark plugs and wires?
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