B31 Mag Gear

[JMW9241]

Hi people I'm building a BSA B31 and need to get the gear which fits on the Magneto. I have looked on ebay and loads are saying they fit but all have different number of teeth. Does anyone know what number of teeth that it should have? Some reproduction gears are also made of aluminium is that a problem?

[Pete Gill]

Hi JMW

Do you mean the gear that fits within the magneto (looks like its made of Tufnell) or the pinion that fits within the timing case that fits on the tapered shaft?
Pete

[JulianS]

The gear which sits on the mag shaft in the timing cover is steel part 65 2334 and has 36 teeth.

The fibre gear which connects the magneto and dynamo within the magdyno has 58 teeth.

[JMW9241]

Hi JMW

Do you mean the gear that fits within the magneto (looks like its made of Tufnell) or the pinion that fits within the timing case that fits on the tapered shaft?
Pete

Thanks Pete its the one that goes onto the Magneto tapered shaft inside of the timing chest driven by the intermediate gear. I think Julian has answered below 👍

[JMW9241]

The gear which sits on the mag shaft in the timing cover is steel part 65 2334 and has 36 teeth.

The fibre gear which connects the magneto and dynamo within the magdyno has 58 teeth.

Thanks Julian, that's very helpful and will help with my search. It is the one inside the timing chest and fits directly onto the tapered shaft of the mag. I don't intend to run a dynamo so won't need the fibre one.