[rowdy]

Well I have a k3 and the weak spot on that was the crank, it snapped the end off about 3 inch from the chain side of the bike.
To be fair it was given a good thrash for a while leading up to the failure, I think most road bikes that have been ridden half sensibly should be ok, don't know how many minitwins that run k3 motors have suffered though.
The engine note did change slightly though for a few weeks prior to it breaking, but I had just changed my lid and put it down to different accoustics from the new lid. My bad!

Exhaust can does come up at a slightly higher level on the k3 in comparison to later models.

Don't worry too much, just keep an eye on the oil and coolant levels and don't go around bouncing it off the rev limiter and she'll be alright.

Edit: My bike was run on a dyno by the co founder of dynapro dynometers, and was told by him that some early k3's slipped through the net with a rev limit setting that was a thousand rpm higher than should have been. He didn't rev the bike to the limiter, but when asked by the dyno owner what it was safe to rev to he said these bikes have a rev limit of 10400rpm, whereas mine hits the limiter at 11400rpm, so being reved that 1000rpm higher than normal probably took it's toll on the engine in the end.