I have a 350cc ohv Twin Port Sloper. The answer will likely apply to all ohv Slopers. Does anyone know for sure whether there should be a head gasket, and if so where exactly it fits (that's not as daft a question as you at first think!). I presently have 3 different sets of advice from owners, and all 3 are in use...: 1: there should be no gasket, just lap the cylinder liner spigot/head joint to ensure a gas tight fit. 2: there should be a copper gasket, it fits inside the head recess so that the top of the cylinder liner spigot presses into it. 3: there should be a copper (or card) gasket, it fits on top of the barrel around the cylinder liner spigot so that it is squeezed by the flat surface of the head. Cheers. Dave
Box number 2 has the money behind it. Part number 15-1066 Cylinder head washer. Looks like a copper washer on steroids which will go on top of the liner.
The single port has a different number (15-1065 ) Don't ask me what the difference is. Make a pattern of the recess in the head then sent it off to Lanni ( coppergasketsus ) after you work out how thick it needs to be. Remember to allow the push rod tube to seal as well