Domes for a Cub

[Ducman]

Its been many years since I've replaced pistons in a banshee and shes been down for a couple of years now.  I have to replace the pistons and domes due to a small chunk of piston above the rings that broke loose, transferred to the other cylinder and squished around and apparently went out the exhaust.  Amazingly the bike was still running half way decent and ran for several hours after the piece came loose.  I know when it happened due to the spark plug gap got closed.  The pistons still move up and down freely and I can't detect any scratches in the cylinder wall.

 

Anyway, the main question.  I forgot which size of domes I was running.  I need to pick a dome size for cub cylinder +4mm stroke running a .12 base gasket and 110 octane fuel, sea level.  I like to have more torque to get my fat ass around in the dune trails without having to get on the pipe all the time.  I think I was running 19cc before and was thinking about running 20cc now but when I talked with TDR racing to order some parts they were talking like 20cc was too much compression with a cub motor.  Back in the day when cubs were a new popular trend everyone was running a bunch of compression with cubs.

 

These are going to be "off the shelf" pro design domes cut for the 68mm bore and blaster piston dome angle.

[Ducman]

Ha ha, I see in my old signature it says 19cc domes, but I dont trust that 100%.  Anyway I would still have asked the same question.  FYI, I never detected any detonation issues in the past but at some point the extra compression is just extra wear and tear on the crank.

[trickedcarbine]

Take the head off, measure the deck height, and call Driveline.