A10 Spitfire Scrambler - Gearbox Sprocket

[Brucie64]

Hi All,

Does anyone know whats the quickest and easiest method to change the gearbox sprocket on my A10. Can it be removed with the gearbox insitu (i.e. removing the clutch) or is it best to remove the gearbox totally?

Regards

[dpaddock]

The gearbox does not have to be removed for this task. Just remove the clutch and inner primary cover. BSA Service Sheets 308 and 310 cover the details.

David

[Brucie64]

Many thanks for your assistance David.

Bruce

[muskrat]

G'day Bruce & David, long lost twins, looking at your avatars. Bruce, while it's apart it might be worthwhile to replace the seal as well if it's been in there for some time. Same for sliding plate felt and crank seal.
Cheers

[BSA_54A10]

And for a little more chain wisedom.
Always replace both sprockets as a set.
Then buy 3 chains.
Put first chain on and when it needs adjusting, replace it with the second ( it will pull through so it is a 10 minute job ).
When second chain needs adjusting, put the 3rd chain on.
When third chain needs adjusting, return the first chain and adjust it.
While each chain is off the bike, clean it properly and lubricate it ready to be reinstalled.

This way you will get 3 chains out of each sprocket set.
You can extend this as far as you like but I have found that any more than 5 chains and it gets a bit too confusing.

[muskrat]

Good advice Trevor, do you boil them in grease as per old skool, I do.
Another tip is to LIGHTLY smear the spline with silastic to stop oil migrating out of gbox, I also use a special nut with a seal to stop oil migrating between the shafts.
Cheers

[BSA_54A10]

When I was riding the SR500 for work I used 5 chain sets. 1 on the bike, 1 in kerro, 1 drying prior to greasing, 1 in the grease tin & 1 ready to go back on the bike in an old empty Duckhams chain grease tin.
But I did do a lot of miles so chain swapping was a weekly job along with oil changes & cam tensioner adjustments .
Only ever boil chains and never had a chain failure.
I also used industrial chain which I bought in 20m rolls as I rather the chain wears than the sprockets.
The A 65 had 3 chains as did the B40 the latter being really important as it had the sprocket as part of the rear drum thus not really replaceable.