I have a Polini 65cc kit that I put on years ago without increasing the rotary duct opening or cutting the crank. So I took old ned apart one more time to do it. Still not even sure what I am going to use to cut the crank, but as I was checking the measurements against the instructions that came with the kit something didn't quite line up right. According to Polini's instructions, it seems like I'dd be cutting the crand in the area that's recessed. I suppose this shouldn't matter as long as the surface of the crank is intact and full width. But I wanted to check with pros. Does this seem right?
Also, looking at the inlet/rotary window, when extending it out 4mm on each side according to the instructions, am I just angling that back in to the intake area? I've done this on a Vespa scooter, but on those cases you are just opening it straight up and down. do I want to get in there, smooth out those ledges you see, then ramp it down to an opening that is 4mm longer on each side? Actually, though, it looks like I don't want to extend it much if at al on the right side in the photo, because i don't want to get too close to that edge, right? So realistically I'll just be extending it on the left.
Any thoughts on either thing would be helpful. Cranks!