Ian and others, any one know of a source of a final drive gearbox sprocket 17 or 18 tooth for a B31 an friend asked me to ask about he has tried most sources, andrew

email (option): warbikes@gmail.com

(Early) rigid, plunger or swinging arm?...The standard sprocket is 19T...Ian

email (option): ian@wright52.plus.com

The boss on latter sprocket for oil seal boxes is bigger diameter than the no seal boxes with a scroll.
Also if you find one carefully check the splines.
A lot of cheap ones , particularly from India seem to have 45 deg slopped sides so while being the correct width will not mesh with the high gear sleeve splines.

email (option): bsansw1@tpg.com.au

To clarify..early rigid B31s use one sprocket, later rigid and plunger models have two sprocket types (oil seal and non oil seal types) and swinging arm boxes have another two types (depending on year and chain width...)

So first the year and model type needs to be clarified before looking for an appropriate sprocket...Note that B Series models use a 19T sprocket as standard. There are some 18T sprockets available as well for some applications..

Gearing alterations are more easily done by changing the engine sprockets which range from 16T-24T...Ian

email (option): ian@wright52.plus.com

And you don't need to remove the clutch which is always a plus

email (option): bsansw1@tpg.com.au

thanks All, will tell my friend to log on to this site to read your wise comments , andrew

email (option): warbikes@gmail.com

Tell him when enquiring about purchasing a sprocket to specify to the dealer that he wants one supplied by Velocette Engineering...
They only sell to the trade but are very good quality products and UK made...Ian

email (option): ian@wright52.plus.com