bbaart
CB750 Enthusiast
A couple months ago I posted an issue that I have on my 81 CB750F. At that time, I called it an engine power surge where cruising at about 5,000 rpm, occasionally there would be what I thought at the time a sudden "power surge" while the throttle is being held steady, almost like I've twisted the throttle. Except that I haven't. And it is only for a fraction of a second, then continues to ride smoothly. Since then I have realized it only occurs in 5th gear, has now changed to happening around 3500 to 4000 rpm, AND most often just after shifting into 5th and with the throttle barely open. Someone posted a response a few months ago suggesting that maybe the clutch was slipping. The more I thought about it the more I thought that made sense because it feels as if the clutch lever is slightly pulled for a split second, the revs increase but the speed doesn't. Its also usually accompanied by a clunking sound. So, I ordered a new clutch, installed it, but that did not solve the problem. So now I am thinking its a transmission problem, something specific to 5th gear. But 5th gear works fine once I get the revs up a little past 4500 rpm. Anyone have any thoughts? Engine has about 75,000 miles on it. I have never split the crankcase on this engine and not looking forward to doing that as it looks complicated as hell.
