A65 layshaft

[sprint]

A friend is currently rebuilding a 72 A65. He finds that the layshaft has around 1/8" endplay when fitted? It has all the correct thrust washers fitted is this the normal amount of layshaft endplay? This was how it was when taken apart and so may be the norm?

Can anybody advise as I am sure it would be much the same as for the A10's even though they have a seperate box?

Thanks

Andy

[Servodyne]

Hi Andy.
1/8" end float is far too much. The book says just perceptible.
Is your friend sure he has the correct thrust washers fitted; there are two of them? The one on the timing side should be 0.113 - 0.115" thick. The one on the drive side comes in 3 sizes, starting at the same size as the timing size to 0.127 - 0.129" thick. In my experience I've had to fit the thickest one every time which gives around 10 thou end float.
You can get the correct thrust washers from Dragonfly.
Hope this helps.
Jim
 

[Sluggo]

*I am not certain I am being helpful here*

But, This way too vague to properly respond.  The reason why is simply apples to refrigerators, Not the same designs other than layshaft & mainshaft and those bumpy bits called gears.

The A65 has a cassette style transmission and most of the parts are fixed to a roundish-oval plate that bolts in to the case.   It unbolts and removes as one large assy. (I can post pix and do some measuring if you like, Got a LOT of A65s)

The Preunit A10 and Singles use a more traditional box assy With an out cover and then the intermediate cover merely locates the layshaft and Main shaft on one end and similarly riding on bearings or bushes inside the case.

2 different animals.

Can you show, pix or properly describe WHERE and HOW you are getting this endplay or slop?  You say when fitted.......... what does that mean? When secured to the Cassette end plate? Or when the whole cassette assy is fitted INTO the case itself??

[chaterlea25]

Hi Andy,
Its been a while since we have heard from you I hope all is well with the A7

A65 layshaft needs to be shimmed down to 3 thou or less,
Its bee discussed on the britbike forum BSA section, many times
http://www.britbike.com/forums/ubbthreads.php/forums/1/1/bsa-bulletin-board

John

[sprint]

*I am not certain I am being helpful here*

But, This way too vague to properly respond.  The reason why is simply apples to refrigerators, Not the same designs other than layshaft & mainshaft and those bumpy bits called gears.

The A65 has a cassette style transmission and most of the parts are fixed to a roundish-oval plate that bolts in to the case.   It unbolts and removes as one large assy. (I can post pix and do some measuring if you like, Got a LOT of A65s)

The Preunit A10 and Singles use a more traditional box assy With an out cover and then the intermediate cover merely locates the layshaft and Main shaft on one end and similarly riding on bearings or bushes inside the case.

2 different animals.

Can you show, pix or properly describe WHERE and HOW you are getting this endplay or slop?  You say when fitted.......... what does that mean? When secured to the Cassette end plate? Or when the whole cassette assy is fitted INTO the case itself??

Thanks for the reply.

As indicated  I am trying to help a friend so do not have direct access to take photos etc. My understanding  is that it is after the assy has been fitted into the  crankcase half that the end float is being measured, which is currently around the 1/8" region. Indications are that this should not be more than around the 3 to 5 thou region?

[sprint]

Hi Andy,
Its been a while since we have heard from you I hope all is well with the A7

A65 layshaft needs to be shimmed down to 3 thou or less,
Its bee discussed on the britbike forum BSA section, many times
http://www.britbike.com/forums/ubbthreads.php/forums/1/1/bsa-bulletin-board

John

Hi John.

Yes it has been a while since I last posted on the forum which in some ways is a good thing, no problems, but I do have a read regularly. My RGS is fine and hope to have it back on the road once the new no MOT requirements starts.

Thanks for the link.

Andy

[sprint]

Hi Andy.
1/8" end float is far too much. The book says just perceptible.
Is your friend sure he has the correct thrust washers fitted; there are two of them? The one on the timing side should be 0.113 - 0.115" thick. The one on the drive side comes in 3 sizes, starting at the same size as the timing size to 0.127 - 0.129" thick. In my experience I've had to fit the thickest one every time which gives around 10 thou end float.
You can get the correct thrust washers from Dragonfly.
Hope this helps.
Jim

Thanks for the reply Jim

Andy