Originally Posted by
Nosedragger
Stock exhaust timing on a 26cc is 164 degrees.
The four port cylinders won't fit the old G-23 two port crankcase as the transfer bowls won't line up correctly with the transfer ports. there is not enough meat on the case to grind it out to fit.
They run just fine on 89, CR is not that high.
props and rpm are 18 x 6 ~ 10, 16 x 8 ~ 12
7,000~8,500 rpm
We are speaking of the Chung Yang hop up cylinders made for the Zenoah 23 and 26cc engines. They are availabe in both two and four bolt versions, have the exhaust timing specs I mentioned, and are recommended to be run with premium fuel.
My Zenoah with the Chung Yang hop up cylinder turns an APC 16 X 8 prop at 10,200 rpms without a tuned pipe.
AV8TOR