1939 Sunbeam B24/25T gear ratios

[SteveCarver]

Hi folks,

I'm new to this forum but have read several posts here and it sounds like some of you might have the knowledge I'm after.  I am working on restoring a 1939 Sunbeam B24/25T and have been searching high and low for information on likely ratios in the Burman box. I admit to knowing next to nothing about trials machinery but the bike is in my workshop and I've committed myself to it as the next project. The bike came to me (loosely put together) with both the 350 and the 500 engine, the latter in frame. The former has had a hard life but may yet be saved. The 500 came from Lithuania (apparently) but is in good order. I digress but the 350 or 500 engine is perhaps relevant as regards gearing. Anyway, the bike also came with two Burman CP boxes. They might be from anywhere (who knows?) but are geared as follows:

#1 Main shaft: 30/23-18/27 Lay shaft: 20, 27/18-18/32,23

#2 Mainshaft: 32/23-18/29 Lay shaft: 18, 27/18-18/32,21

Are these any use? I know that the 500s were originally fitted with the heavier/stronger BAP box, so I'm currently on the look out for one.

Any help or hints would be gratefully received.

Best regards,

Steve

 

[section swept]

I could get shot down in flames here but I reckon you have with the #1box that’s for the 350 and #2 is for the 500. You may get more useful help and information from Old Bike Mart, there are many subscribers to this paper and some are very knowledgable. You may even be able to make contact with a few Sunbeam owners. Have you tried the Sunbeam Owners Club??

[thumperladdie]

Hi Steve

The Marston Sunbeam Club and Register is the club for pre WW2 Sunbeams. 

http://www.marston-sunbeam.org/

[SteveCarver]

On 17/04/2018 at 10:07 AM, section swept said:

I could get shot down in flames here but I reckon you have with the #1box that’s for the 350 and #2 is for the 500. You may get more useful help and information from Old Bike Mart, there are many subscribers to this paper and some are very knowledgable. You may even be able to make contact with a few Sunbeam owners. Have you tried the Sunbeam Owners Club??

You might be right. I take OBM but never thought of writing to them for advice. Thanks.

[SteveCarver]

12 hours ago, thumperladdie said:

Hi Steve

The Marston Sunbeam Club and Register is the club for pre WW2 Sunbeams. 

http://www.marston-sunbeam.org/

Thanks. I'm a member but as far as I know, no one in the club has one of these. I'll whizz off and email to the technical sec to ask for advice. Ta!
 

[section swept]

46 minutes ago, SteveCarver said:

Thanks. I'm a member but as far as I know, no one in the club has one of these. I'll whizz off and email to the technical sec to ask for advice. Ta!
 

Hope you get the info you need.

[thumperladdie]

Bonhams Auction this weekend – lot 89

A Canterbury Trials Sidecar,

mid 1950's, has undergone a full restoration since acquisition forty years ago by the current owner, aluminium-skinned finish.

SALEROOM NOTICES

This sidecar is that of the same type used by Ariel works rider Frank Wilkins in the International Six Days Trial. Included with the sidecar are fittings for Ariel HT5 and mid 1950s Triumph spring frame models together with a Canterbury spares catalogue.

The online catalogue includes a photo