Gearbox model.

[ianw1]

Can anyone identify which gearbox I have in my 1938 Silver Streak please?
Stampings on the shell are SHPB 25474.

[dave16mct]

It's the later Burman HP1, the smoothed over one. It's a lightweight Burman compared to the CD.
Dave.

[Rob Harknett]

Ashampoo_Snap_30 March 2021_19h54m01s_001_.jpg

You probably have the gearbox seen here on a 1939 250 It is the finale version of the HP gearbox, 1-HP. I say " probably " as this box was fitted in other marques. Modifications may have had to be made to the plates to get it to fit. Perhaps also line up sprockets. If your box was not intended for an AJS. You will see the old HP box is fitted in 1938 sales cat's, to 250 & 350 models. This new 1-HP box may have been phased in or old artwork used on the sales cat's. In 1939 only 250's had this 1-HP box. There seems to be no Burman literature available for this 1-HP box.

[ianw1]

As always gentlemen, thankyou. Do you think this gearbox was fitted to the bike as standard at the factory or was it fitted by an owner later?

[Rob Harknett]

Type fitted by the factory, on a 1938 250 & 350 only. 1939 250 only. You do not state model. Also as stated earlier, it may not have been intended for an AJS, if so it would need some bodging to fit in plates.

[ianw1]

Rob, do you mean the model of bike or model of gearbox?

[Rob Harknett]

Rob, do you mean the model of bike or model of gearbox?

Bike model.

[ianw1]

Sorry Rob, 1938 350 Silver Streak.

[Rob Harknett]

Sorry Rob, 1938 350 Silver Streak.

64 my bikes.jpg

You should just about see the 1-HP on my 1938 350

[ianw1]

Yes I can Rob, thank you for posting.