The problem I had this weekend with my Ninja 12 is that the carb. popped out. It didn't twist or run away (thank God) it will just pop out and cut off. I checked my servo end-point when I installed the engine, but the first time this happened, I turned it down a couple more clicks just to make sure. But, it happened again. After the 2nd time, I checked the pinch bolt and it wasn't loose. It was still tight but the carb was out. So, I put loc-tite on the pinch bolt, tightened it down hard and went back out. In 2 min it popped out again. The carb is no-where close to touching the break disc so it's not that either. And, it slides smoothly with no binding at all.

I'm pretty much out of ideas on this one. The only thing I can figure (and I know this sounds crazy) is that i'm pushing down too hard on the carb when installing it and the crank is pushing it out. I'm going to check the bottom of the carb to see if there are any marks on it.

Other than that, i'm out of ideas. I'm considering putting "safety wire" on the carb to keep it in. I figure either that will hold it in and that will be the end of it, or something else will happen and i'll see where the problem really is.

Any other suggestions?

Maybe the pinch bolt has a short thread.So even though you have tightened
it thinking it is tight perhaps the nut is against the end of the threading.Try a small washer between crankcase and nut on thread and tighten it down.Then see what happens.