The microfiche shows that you have a 21 top 43 bottom gears I would check to make sure this is right. Then I would drop a tooth on top and see how that works. You may loose a little top speed, but i'm not sure what you are looking for. If you don't care about top speed you could drop two teeth on top or go to a 44 tooth bottom gear. Try to find some one with used gears so that you can experiment with it and find what you are looking for.