CCC, I sure like the design here. I have decided to use a GC160 with a CVT in my next build, and this thread simply confirms, and inspires me in that choice. It seems to me the GC series Hondas are just about the very best choice in a 4 stroke for a motorized bike..unless you need more power..(or I should say want more power, cant imagine needing it!) due to the aftermarket performance parts available for the GX series engine, and none for the GC. A big factor for me was the weight...the GC160 is the lightest weight 5 hp motor in the industry. This seems to be a no-brainer especially at its low price, low vibration, and the vertical cylinder configuration is great for a MB...and you have solved the engine center problem with the mod to the CVT output sprocket.(which I will unashamedly copy on mine).Thanks for shareing!
OH..and for those interested..here is a weight comparison on the Honda small engines:
GX35= 7.6 lbs
GX50= 12.1 lbs
GX100=23.4 lbs
GC160= 25.4 lbs
GX120= 28 lbs
GX160= 33 lbs
(GX160 clones generally weigh a pound or 2 more than the Hondas, and some of them 3 lbs more we have found)