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High RPM’s

surfish84651

CB750 New member
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Payson, UT
Hello everybody. I have a 1996 cb750 nighthawk that when I am on the freeway and riding at 70 miles per hour, my RPM’s are at 9500. Now, I’ve done a bit of work to this bike making it more of a cafe racer/ brat bike. I have not done any work to the engine besides maintenance stuff, carb sync, oil change etc. I have a Dime City Cycle electronic tachometer rather than stock tach. It is wired into the same wires as the sock one though.

9500 RPM’s seems high to me at 70 mph. Compression is around 110 on 1, 3, and 4. Cylinder 2 is at 90 psi. I haven’t done a leak down test to see what is causing lower compression. However, does this sound like a issue with the engine or maybe the tachometer is off in its reading? I’ll hook up a second tach reader and see what that says. Thanks guys!
 
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