wow that was quick, dont forget to torque up the magneto bolt/nut tight on re-assembly, its common to find people just tightening these things 'best they can' only to end up with a sheared woodruff key later!!!
try and get a manual for it and check the ignition timing settings, however until then you may see some marks on the ignition stator and the engine case that should align?...just a guess though I am not familiar with the bike
Have any of you ever met Dan? he's got a bike shop in Idaho and a great website that he imparts his great knowlege for the likes of us lot
click on INDEX
http://www.dansmc.com/
a word of warning, never cut up a good one unless you know what you'll find inside, I did this and found nothing! it was only restricted by the tube in the header pipe
Andy post up the number on the pipe you just cut up with nothing inside
you would need to clean the top of the piston to see the size that is currently fitted...dont take it for granted that it it is currently fitted with a standard piston