Hello mark.

You need
External diameter: 38.18mm
Internal diameter: 14.46mm
BSA PN: 65-2316

The new rubber ones should have some tension over the shaft,
So it may be the correct one.

If you search eBay or google with the PN, you can compare to pictures.

Noam.

email (option): noam10@gmail.com

I saw that seal with the 14mm ID on ebay it must be a missprint all the others on the net are 20 mm as is mine. The pinion shaft is about 20.5mm. I have two spare motors and there all the same 20.5 mm.

email (option): mhadfield35@yahoo.com.au

Hi Mark.

Sorry if I was mistaken.
I have few correct spares at home, but I am al NL at the moment,
So cannot measure.

It also looked a bit small to me, but I found the same measures in other sites...

I think that better info is:

Oil seal for MO1L magnetos as fitted to B31, B32, B33, B34, M20, M21, M33 models.
OD: 1+1/2" (38.2mm)
ID: 13/16" (20.6mm)
Depth: 3/8" (9.7mm)

OEM: 65-2316


Cheers,
Noam.

email (option): noam10@gmail.com

The 'oil seal' originally fitted predated the introduction of modern lipped seals and (especially when old) they are far less effective than a modern equivalent...

These are readily available and would be the best choice as an upgrade to replace the original type...Ian

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

I have found and ordered a modern seal.The seal supplied is as hard as bakelite. So thanks for the advice chaps.
Haddy

email (option): mhadfield35@yahoo.com.au