[goat67]

Thanks for the reply,

Size:
• 21 mm: 50cc to 100cc engine
• 24 mm: 50cc to 100cc engine
• 26 mm: 75cc to 125cc engine
• 28 mm: 75cc to 125cc engine
• 30 mm: 100cc to 150cc engine
• 32 mm: 125cc to 200cc engine
• 34 mm: 125cc to 250cc engine

From the info on the web site, I was thinking on going with the 30mm but maybe could go bigger?

I wish I could get a head to port but I am not sure on what one to order and I have never done it before so kinda leary on doing the port job anyway.