(07-16-2020, 11:52 PM)Tom Smith Wrote: Light weight 820 piston
Tom, Is that a std piston that has been machined out?
(07-17-2020, 04:01 AM)Terry Bentley Wrote: I am glad to find out after only 30+ years of playing with 820's that they have been run completely wrong. Guess I will ditch the oil clutches on those step cranks and replace with dry ones. Throw away the expansion chambers I made for them back then and quit reving to 13,200. Now I find it is unsafe above 12,500, sure dont want to blow them up. Maybe buy a pair of old GEM mufflers. You know they sound so sweet on the motors.
Sure hope I dont find out that boring out the chrome and relining with cast iron sleeves doesnt work either. That would really bum me out.
Terry, Steve is talking about the engines that are being built with the parts available TODAY. My new 820 from a reputable engine builder lasted 5 events not being turned over 11,500 on 10 oz per gal castor. Crank had wear spot and it broke the rod.