I have seen relatively stock motors take 62-68 pilots with ghose carbs, I was a lil baffled but it wants what it wants. I usually keep adding pilot till the screw operates
Stick a peice of solder in the cylinder parralell with the wrist pin , bend solder so it touches the cylinder and domes mating area, kick the bike measure the solder
As stated 18cc domes are race gas domes regardless of static compression with your set , go buy 110 octane put it in , if plugs don't back out u found your issue , do a leakdown domes on the ragged edge will deto from lean condition