1979 KZ-750 Twin, rebuilt about 5k miles back and running really good now: This problem that is ongoing has me wondering if my bike is safe to ride:
A while back, I was sitting at a light with my engine idling and I heard a quick metallic "clack" kind of sound and I felt a little jerk in the handlebars. It clearly came from the engine and it sounded like something hitting something.
I have heard it maybe twice since then, each time just a little sound and I feel it through the handlebars. No effect in performance.
Today when I came home, I was idling in the garage when I heard a much louder clack and it stalled the engine. I pulled the spark plugs and the cam chain adjuster cover. I turned the engine by hand and saw the valves moving, no resistance. Cam chain still properly adjusted and the tensioner was moving in and out correctly.
I checked compression and it was still very good (160 both sides)
I put the plugs back in and it started and went into gear normally, but I am greatly concerned this thing is going to blow up on me.
I don't think it could the cam chain, since it is still OK. Cam chain guides? Don't know, they looked OK when I did the rebuild.
Don't think it's clutch related, since it was in neutral when it does it.
I was HOPING it might be the starter clutch which is why I took it off and checked it, but it looked really good and has never seemed to give any problem so I don't think it could be that.
Could this be the primary chain? The internal balancer? Anybody have a clue what this could be?
I am pretty much afraid to run it at this point and just shooting in the dark.
1979 KZ-750 Twin
