S/a a10 gearbox sprocket removal

[Cleve]

Hi, hope you chaps can help, I'm trying to get the gearbox sprocket undone, I'm sure it must undo clockwise? (I'm gearing down from 21 to 19

Thanks

Cleve

[RoyC]

Hi, hope you chaps can help, I'm trying to get the gearbox sprocket undone, I'm sure it must undo clockwise? (I'm gearing down from 21 to 19

Thanks

Cleve

Why not change the engine sprocket instead, that way you won't upset your speedo accuracy.

[ellis]

And you don't need to strip the whole chain case and clutch to do it.

ELLIS

[Cleve]

Hi Ellis/Roy,
thanks for reply, I've got it all stripped, have a belt drive so clean job, I only put the 21 on last winter, but I can't remember which way the thread goes and can't get it loose, so before I apply more force I hope someone can confirm undo direction 😊 21 is hard work in traffic...

[ellis]

Hi Cleve.

From what I can remember it was a standard right hand thread.

ELLIS

[duTch]

 As ellis says they are Right hand thread.

 As Roy says;
 

...Why not change the engine sprocket instead, that way you won't upset your speedo accuracy.

 If it's a standard speedo it'll already be wrong, so going to a 19T will put it right, but I expect the difference will be extremely noticeable.

[Cleve]

Thanks again,  I will try undoing it anti clockwise tonight.

Re the speedo, I guess I will have been under reading with the 21 tooth sprocket

Regards

[Greybeard]

You may be able to check your speedo against a SatNav. They are very accurate, (as long as you are not riding up and down hills).

[trevinoz]

19 is standard so the speedo will most likely be calibrated for it.

[Butch (cb)]

You may be able to check your speedo against a SatNav. They are very accurate, (as long as you are not riding up and down hills).

Either Lincolnshire or the Essex badlands would be best for a calibration run then I guess.

[Whipstrut]

Quick query, does anyone know the actual thread size of the nut? Thinking of possibly making one from hex stock.

[RichardL]

 As ellis says they are Right hand thread.

 As Roy says;
 

...Why not change the engine sprocket instead, that way you won't upset your speedo accuracy.

 If it's a standard speedo it'll already be wrong, so going to a 19T will put it right, but I expect the difference will be extremely noticeable.

 

Dutch,

Did you mean, "...the difference will not be extremely noticeable," meaning the difference in the speedo's report, or did you mean the difference in riding with the 19T sprocket will be extremely noticeable."?

Richard L.

[duTch]

  I'll be adventurous and guessing at 20 tpi that we would call Cycle thread like most other BSA threads- you obviously don't have sleeve gear handy to measure the threads on that...

 Richard you posted while I was slowly composing...

.....Did you mean, "...the difference will not be extremely noticeable," meaning the difference in the speedo's report, or did you mean the difference in riding with the 19T sprocket will be extremely noticeable."?......

 No I think I meant what I said (hard to believe I know ), that the difference will be fairly obvious.....

[coater87]

I bought a 5/8 x 20 tap and made my own too.

 Lee

[chaterlea25]

Hi

Quick query, does anyone know the actual thread size of the nut? Thinking of possibly making one from hex stock.

Lee, I think he is asking about the gearbox sprocket nut??

Whipstrut
If you intend to make one I would include an oil seal as on the SRM product
http://www.shop.srmclassicbikes.com/product/gearbox-sprocket-nut-oil-seal-bsa-pre-unit-swingarm-models

John