Porting before an after much difference?

[banshee07]

The first motor mod I did was I bought ported 370cc cylinders off a guy on another site. Not sure how good of a job it was but against my buddies piped banshee I could play with him in 5th gear real easily. Before the Pistons and cylinders we were neck and neck. And from what I read the 20cc bigger cylinders isn't what gave it the power. It was the porting. Ran that setup with fmf fattys, kn and the rest stock for couple years. Then eventually took the stock crank out. I then put a 4mill hotrods, noss head with I think 21cc stroker cut domes, timing plate at 4 degrees, boysen reed pedals, now a 400cc banshee. It really rips. Me and my gf on it. So about 320-330lbs on it play with my buddies pipped banshee.

Edited April 5, 2015 by banshee07

[#1JUANstunna]

The first motor mod I did was I bought ported 370cc cylinders off a guy on another site. Not sure how good of a job it was but against my buddies piped banshee I could play with him in 5th gear real easily. Before the Pistons and cylinders we were neck and neck. And from what I read the 20cc bigger cylinders isn't what gave it the power. It was the porting. Ran that setup with fmf fattys, kn and the rest stock for couple years. Then eventually took the stock crank out. I then put a 4mill hotrods, noss head with I think 21cc stroker cut domes, timing plate at 4 degrees, boysen reed pedals, now a 400cc banshee. It really rips. Me and my gf on it. So about 320-330lbs on it play with my buddies pipped banshee.

So what bore are these cylinders?

[banshee07]

66.5 or 67mm I think. And now with the 4mm crank it works out to 400cc going off a equation on how to figure out cylinder cc