Bsa b31 dynamo

[750rideruk]

Please can any of you fine people tell me the diameter of a B31 dynamo. I am building a bike but want to leave off the lights. Currently have an alloy tube in place of the dynamo but is too big to allow me to fit the float bowl behind the carb. Many thanks in anticipation of your replies

[Derek996]

3"

[kenif]

Hi,
Lucas E3L are 76mm diameter.. Hope this helps..

[leon bee]

I have a 650 Triumph piston holding my magneto down.

[JulianS]

The 3 in E3L is for 3 inch diameter body.

The E for eccentrically mounted armature.

L for long body.

If there is an M it indicates it was magdyno mounted.

[750rideruk]

Thanks Leon Bee. Good idea. which i shall steal.

[leon bee]

I even shined the old, used piston up a bit before installation.