Has anyone Though about building a 80cc engine from a 40mm stroke engine? I saw a piston cylinder and rings with gaskets on ebay, 50mm bore that BGF says will work with a standard 66-69 cc head. If I had a 40mm stroke engine I would give it a try.
That requires a bottom end with a long connecting rod.Here it is.
BT100 100cc IRON sleeve cylinder turn 2-stroke 80cc to 100c motor bike engine 49 | eBay
This cylinder is upgrade 80cc into 100cc ( only for long connecting rod bottom end). 1 of 100cc steel sleeve cylinder (#BT100) ( 40mm intake not include, need buy separated ). use original 80cc head is ok.www.ebay.com