Hi,Matt
You are right, after I have it compared, the stopper pin is in the centure of piston, also something what I found the differently are Wisco piston has flat top of piston(the top end is like mirror), and single ring that I described at first.
I gotta MC21/MC28 stock trany compared, they are different, MC21 has close ratio and now i have stock MC28 tranny on my MC28, but I will try on MC21 to HRC set, becasue I think MC28 trany will not be very interesting for me, I mean not even rev fast, but smoothly goes, correct me if i'm wrong....
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1996 HONDA RS250
1995 MC28 NSR250 SE red/white/green
1994 MC28 NSR250 sp W/ RS250 engine