Can anybody please tell me the piston to cylinder clearance when you rebore a 420 barrel. I need the specks for a Mahle piston not a Wiseco one as I have been told that they expand at different rates.
Cheers Bill
Bill .0025 to .003 thousands Later Gary
Nah, can't be so.
3 mm = .118 "
Me thinks Gary meant .025-.030".
Larry P
You mean .0025" to .003" (per side) [?]
Yes thousandths. Poor math skills it said on my report card. We probably have poor Bill all cornfused now.:D
Larry P
My 1980 KTM owners manual which oddly lists the clearance for a 400? as 3.0-3.5 thousanths, which would be total clearance, not per side, but doesn't list a 420, which began in late 79. I would think it would be similar. Depending on how you ride the bike at first during break in and how much time you put on it before racing, I would prefer the tighter range for longevity. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
75 Can Am 175 TNT & 77 250 Black Widow
1976-78 RM & 77-79 PE Suzuki's
74 CR250M 07 CR125R & CR150R
I was meaning total clearance but it is from memory.
Larry P
Thanks guys. I was a little confused but I finally made up my mind to go with .003".
Keep up the good work.
Cheers Bill