ZA50 & Metra 80

To fit the 52mm cylinder skirt of a Metra80, or any Puch 80 kit, you need to open up your cases. Most people use a dremel by hand and do an okay job. The best way to do it is to use a mill and have it nice and even, so that the skit sits evenly in the case and transfers heat uniformly, but usually it's not a big deal. To open my cases up, I picked up two 60 grit 2" flap wheels, and a 120 grit 2" flap wheel. They chuck right into your drill, and 2 inches is almost exactly 52mm. So you simply sand away that material, leaving a wonderfully nice smooth surface. It took about 10 minutes of drilling, including some time to change the wheel after it staretd to get dull. It came out very nice, much better than a dremel job. I also took a nice new dremel bit and opened up the ports to match the gasket. They are quite large. The 2nd speed clutch in my bike has been flipped, and it looks a tiny bit marked on the inner side, but I'm not sure why this would be. Doesn't seem to be a problem to me, though.

I'm having some trouble with the actual cylinder, but that will be saved for another post.