Quote:
Originally Posted by xb-60
Chas - why a light flywheel? If using tall gearing, wouldn't I need to keep the flywheel close to standard weight?
Glen
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Yes, you would-but a heavy wheel will make a little engine's task harder to achieve what you want above. You could best use a heavier wheel by stroking as Brent suggests to aid torque production off-idle. You're saying 'tall gearing'. That means lower numbers like 3.31, 3.07 and below. I said 'steep' gearing meaning 3.77, 4.11 and higher. You said high top speed was not important to you so other than noise at cruising speed, a steep gear is beneficial to the attributes you want. Plus a light wheel will contribute to the rapid throttle you want and accelerate the crank to 7K more quickly.
Example-I switched from a 3.77 to 3.31 and gained 11MPH at 6200RPM with the same tire. I have a 33 pound wheel so there was no penalty to decrease leverage---also about 400 pounds of torque from about 2500 to the 550 pound peak. You need to
increase leverage with what your planning.
As Brent said earlier, you've got to compromise some areas to get benefits in other areas.