A10 engine sprocket

[Goldy]

In the bits that I have aquired for my A10 build I have two engine sprockets. 18t and 21t. The specifications seem to list both but which should I use. Any thoughts please.

[BSA_54A10]

The lower one is for side car use or trials / trails .
The higher is for road / touring.
Which one suits your riding best is up to you.
I would try the bigger one first.
That will yield a much better mpg but make life harder on the clutch.
If you are not happy then try the smaller one.
This will make life much easier on the clutch and allow you to accelerate much quicker which is good if you are going to use the bike as daily transport as it will keep pace with modern traffic much better and if you ride lights on will keep the dyno spinning faster so keep the battery in a higher state of charge ( good for bikes with blinkers).

You might just be able to run both with the same primary chain if it is in good condition bur the smaller willrequire you to shorten the primary chain if you intend to use it full time ( assuming that it is a SA model) .

[dpaddock]

I guess we forget sometimes that the A10 was produced in many guises. Please, please state the variant and year when you post to this forum.

David

[Goldy]

I am building a machine from bits, I only started with a frame and that is the problem, I cannot specify year and model, and so the help from this forum is of great value. - Thanks