Gearing up for a sidevalve

So Arthur Pentney (OBM Letters July) likes his Norton sidevalve solos but not his BSA M20 which was “somewhat heavy and ponderous and lacking cornering ability” – could this be because he was talking of a rigid model with girder forks?

Not so the postwar 600cc M21! My plunger one with teles and the wonderful eight-inch front brake is a terrific steed for getting around town.

I’ve had it for many years and did tens of thousands of miles on it, combo and solo, with a 16-tooth sidecar sprocket – at a max speed of about 45mph!

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I always knew it could pull a much higher gear so eventually l put a 19-tooth engine sprocket on.

Read more of this Letter and other Letters, Opinion, News and Features in the September 2019 issue of OBM – on sale now!

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