[wireburn]

Hello 2-stroke enthusiasts and engine builders! I'm looking for comments and critiques of a billet cylinder I am designing for my stroked Horizontal Minarelli scooter motor. I seem to have more time than money lately and since I happen to have access to CNC machines and programming software I figured I could build a functional (even fast) alternative to the cast aluminum off-the-shelf options available. The design is patterned after some big water toy motors I've seen on the Internet, but scaled down and provisioned for my application. My intent with this design is to provide a way that I can build my own water-cooled cylinder at a reduced cost compared to the high-end options available.

The design incorporates a wet CNC ported liner, an adapter block that serves to remove the limits of exhaust width while injecting water into an otherwise air-cooled motor, a modular head with engineered squish velocity, and an exhaust stub which allows for a slip-joint exhaust pipe connection.

Engine parameters are as follows:

Bore: 52mm
Stroke: 47mm
Swept Volume: 99.8cc
Volume Under Piston at TDC: 8.9cc
Uncorrected Compression Ratio: 12.2:1 (93 octane pump gas)
Corrected (Trapped) Compression Ratio: 6.5:1
Exhaust Duration: 197°, 62% of bore width
Boost/Aux/Main Intake Duration: 126/128/130°
Blowdown: 33.5°
Target RPM at max power: 10750 (ring flutter occurs at 11250)
Custom Intake with V-Force reeds (384A)
28mm Keihin PWK
Custom Tuned Exhaust, 33mm stub out
Tuned CVT Transmission (holds RPM at a steady state regardless of acelleration or throttle position)

Fire away!

-Mike