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#2 cylinder ??

Ryanbush580

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I have what I believe is a 81 cb750 I am having issues with one cylinder not doing something right I know it has spark I am pretty confident in the carbs being clean any advice greatly appreciated
 
checked compression? checked valve clearances? unless you had the carbs ultrasonically cleaned there is still a very good chance you have a restricted passage. More then likely though it will have low compression.
 
checked compression? checked valve clearances? unless you had the carbs ultrasonically cleaned there is still a very good chance you have a restricted passage. More then likely though it will have low compression.



What causes low compression I should have checked it first I know but all the others seem fine
 
It'll rev up to 4500 but kinda bogs down after that and some times letting off throttle it'll stick around 3k
 
These are notorious for the valve clearances going tight holding the valves open which drops compression and if run long enough burns the valves. They wont run right if compression isnt at least around 150 psi, higher would be better. These carburetors are very picky to engine vacuum so poor engine condition makes carb problems worse. Compression check is imperative. If they are low no point going any farther till you get the engine mechanically sound.
 
Doesn't rev over 4500 rpm? Are you running pods? Compression, valve clearance, carb cleaning (sometime multiple until you get it right), no vacuum leaks, carb balance, stock airbox (pods CAN work with much work, I've heard). No short cuts.
 
Doesn't rev over 4500 rpm? Are you running pods? Compression, valve clearance, carb cleaning (sometime multiple until you get it right), no vacuum leaks, carb balance, stock airbox (pods CAN work with much work, I've heard). No short cuts.


I cleaned the carbs 3 times now 4 but it is running on all 4 now still have the rev issue could it be timing
 
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