does the .20 over add anything or is the performance gain all coming from the bump in compression?
Not really. Overbore is just to freshen the bore and make it round again. Mine was already .05 over from the first build at 30k. My machinist went to .20 and I assume that's where he needed to be to get it where he wanted.
Is there any way to tell which cylinder jug goes where, front or back and does it make a difference?
The pistons are machined to match the jugs.
As long as you keep the pistons with the jugs they are supposed to go with you are fine.
Front or rear doesn't matter.
The pistons are machined to match the jugs.
As long as you keep the pistons with the jugs they are supposed to go with you are fine.
Front or rear doesn't matter.
That's what I was hoping for, I have new pistons and will set the ring gap and keep the piston and rings with the cylinder used to gap the rings.
OK, got the engine back together with 10 to 1 pistons, rode it for the first time today, went about 20 miles, really a noticeable difference. I will ride it to work next week, 30 miles each way, should be a good break in.