My guess is the Harley belt is 14 mm pitch
making the large 72 tooth pulley giving
a pitch diameter of 12.63 inches. Near ideal.

The smallest pulley is 28 teeth giving
a ratio of 2.5714286

Not ideal yet
--  Paul Lamar ...No rotor no motor.

So far I've learned that Harley uses both 8mm and 14 mm belts.  The
larger belts are used on their fuel dragsters and surely are adequate
for my humble little single.  The 2.57 ratio is not ideal but I would
take it gladly.  It is better than a 2.17.   The availability of the
sprockets is exciting, unexpected good news.  Jerry

If you can find the big pulley in 8 mm pitch 72 teeth the
smallest pulley in the Goodyear catalog in that case is 22 teeth
or a ratio of

-- 72/22   = 72 / 22
= approx. 3.2727273

If 70 teeth the ratio becomes
70/22   = 70 / 22
= approx. 3.1818182

The key is finding the big 70 or 72 teeth Harley sprockets in 8 mm pitch.

Paul Lamar ...No rotor no motor.

Don't forget to check the aftermarket, which will have a bunch of other
sprocket sizes to pick from.  HD isn't the only outfit using rubber band
drives, and the custom guys use a wide range of engine/wheel combinations.

Keith

The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2006 All world wide rights reserved.