Interference Fitment

The degree of "tightness" on various fits in/on an XV are bewildering. Once you flatten the washer and turn out the nut on the right end of the crank, the pair of gears held slide right off. On the left end, the rotor is a taper fit that can be so snug that a three-pronged puller must be tightened on with a pneumatic ratchet while heat is applied.

While contemplating truly big (108-110mm?) bores, I heated an 1100 cylinder with a MAP gas hand torch. After fifteen seconds, the cylinder dropped right off of the sleeve. There were corrosion streaks down the sleeve where something had leaked inside the barrel. This had come out of a complete engine a couple of days before. I have a 920 barrel with the sleeve rotated out of true. I heated it for ten minutes, tapping it with a mallet. No movement. It went in the press. At 3000 pounds it started to move. The exposed sleeve gleams like it's chromed. We've only been able to take it up flush with the aluminum base. Now to cobble up a brace to get it out far enough to turn it until it is oriented properly. My guess is that it was mfg this way and it cleared the flyweights okay. But the cut-outs being turned makes me nervous. The pisser is that it is otherwise cosmetically perfect -- something that is relatively rare on used cylinders.

More to come . . .

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