Hello everyone,
I'm new to the board and am wondering about some problems that I'm having with a 1980 KZ750 that I recently purchased. After reading a few posts from this board, I have some ideas but would like to get your input.
For starters, it has no power below 6000rpm. In order to drive the bike, I have to rev it to 3000, slip the clutch and give it full throttle. It responds by barely moving and almost dying. Once the clutch is fully engaged, and the bike is moving, it slowly accelerates, (still at full throttle), but sounds like it's missing on at least one cylinder. When the rpm reaches somewhere around 6000 or so, the miss seems to go away, (it could just be that it's at such a high rpm that I can't hear it anymore), and the bike finally starts making a little power. At that rpm, the accleration feels the same as an older 175cc 2-stroke dirt bike; probably around 30hp or so.
I've checked the plugs, they're new but are heavily fouled. The ignition coils are Accel, along with the plug wires. The bike is definitely running rich at idle. The stock airbox has been removed and replaced with individual carb air filters. The carbs appear to be the Keihin 34CV stock units. My guess is that the problem is a carb issue, but it could be ignition.
Somewhere along the way, one of the previous owners converted the original electronic ignition to points. I don't know where he got the parts or why he would do such a thing, but that conversion might be part of my problem.
The bike runs smoothly at idle; it revs just fine. Throttle response at idle isn't very good but then again, I'm not sure how these bikes are supposed to run from the factory; I just know that it shouldn't take 3000rpm, full throttle and slipping the clutch to make it go.
Any information/advice would be greatly appreciated. Thanks from Mesa, AZ.