Originally Posted by
Booger1
If the bike has no torque converter,I would be pretty much direct drive.You would have to compress the fluid in order to lose power,that isn't going to happen.
Looks like there could be vanes in the system though,meaning torque lose or gain,depending.
Efficiency of fluid drive is real close to chain drive.About 95% for fluid/98% for chain.
You may want to revisit your numbers. Fluid-drive is efficient on large powerful systems, but on something as small as a bike with the small power-output, you're presented with a lot of drag from the seals.