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G: Gearbox Burman tales

vibrac

Well Known and Active Website User
VOC Member
I have recently been turning out my gearbox stash and delving into the jungle of Burman nomenclature, and as others have found its all a bit confusing, so in my screed below I have added a o_O where I am unsure and would like some conformation, correction or additional information.

Burman made a lot of gearboxes for a lot of bikes, post war the BA and CP boxes and others, We here are interested in specifically the BAP box and we all know the BAP box with the adjustment slot at the bottom was fitted on the Comet and I believe it was also fitted on the Panther (with a different main shaft) and perhaps other makes o_O

In 1952 ish Burman working it is said with AMC, bought out a range of GB boxes to replace the old range. the new range are often colloquially referred to as the B52 range o_O. Burman claimed they were better at holding their oil and had improved gears etc etc. They went on to be fitted to a range of machines AJS Matchless Arial o_O etc.

What I did not know however, until I dug into my stash, was they made a GB box with an adjustment slot at the bottom. I have the makings of 4 these boxes and they are all stamped with a prefix GB29 (which is what I will call them here, for want of a better name). These GB29 boxes I understand went onto at least the Cleckheaton monsters in the mid 50.s and perhaps others o_O. Now I dont think the GB29 was ever factory fitted to late Comets o_O perhaps Vincent or Burman were simply running down stocks of the old BAP gearbox and/or dumping them on Comets as they had not been redesigned or updated since 1950, Otherwise either the new GB29 boxes went elsewhere or were not available until after 1954 (my GB29’s are dated 1956-7) and I don't know exactly when Panther started to use the GB type o_O.

What however is important is that looking at one on the bench against a BAP case it does look as if one would fit a Comet with ease, albeit with either a BAP/Vincent main shaft (or nowadays with another clutch or Belt drive). I am supposing in fitting one you would benefit from an increased range of ratios available via the wide range of GB boxes sold to different bikes, the claimed oil tightness, other improvements and also from the fact that from visible RH end its a job to see the difference from a BAP. Now I can not believe I am the first to notice these similarities and possible opportunities in the GB range, so what have I missed?
 
Last edited:

mercurycrest

Well Known and Active Website User
VOC Member
Tim,
The remaining Panther Gear boxes were acquired by the Club from Cleckheaton and Robin B. ended up with them to sell. He'll know the answers for you.
 
Last edited:

delboy

Active Website User
VOC Member
I have recently been turning out my gearbox stash and delving into the jungle of Burman nomenclature, and as others have found its all a bit confusing, so in my screed below I have added a o_O where I am unsure and would like some conformation, correction or additional information.

Burman made a lot of gearboxes for a lot of bikes, post war the BA and CP boxes and others, We here are interested in specifically the BAP box and we all know the BAP box with the adjustment slot at the bottom was fitted on the Comet and I believe it was also fitted on the Panther (with a different main shaft) and perhaps other makes o_O

In 1952 ish Burman working it is said with AMC, bought out a range of GB boxes to replace the old range. the new range are often colloquially referred to as the B52 range o_O. Burman claimed they were better at holding their oil and had improved gears etc etc. They went on to be fitted to a range of machines AJS Matchless Arial o_O etc.

What I did not know however, until I dug into my stash, was they made a GB box with an adjustment slot at the bottom. I have the makings of 4 these boxes and they are all stamped with a prefix GB29 (which is what I will call them here, for want of a better name). These GB29 boxes I understand went onto at least the Cleckheaton monsters in the mid 50.s and perhaps others o_O. Now I dont think the GB29 was ever factory fitted to late Comets o_O perhaps Vincent or Burman were simply running down stocks of the old BAP gearbox and/or dumping them on Comets as they had not been redesigned or updated since 1950, Otherwise either the new GB29 boxes went elsewhere or were not available until after 1954 (my GB29’s are dated 1956-7) and I don't know exactly when Panther started to use the GB type o_O.

What however is important is that looking at one on the bench against a BAP case it does look as if one would fit a Comet with ease, albeit with either a BAP/Vincent main shaft (or nowadays with another clutch or Belt drive). I am supposing in fitting one you would benefit from an increased range of ratios available via the wide range of GB boxes sold to different bikes, the claimed oil tightness, other improvements and also from the fact that from visible RH end its a job to see the difference from a BAP. Now I can not believe I am the first to notice these similarities and possible opportunities in the GB range, so what have I missed?
Hi Tim,
For your interest, the Panther book I have says they used a Burman GB29A box from 1958. It implies that all post-1939 boxes are slotted at the bottom.
Cheers, Delboy.
 
Last edited by a moderator:

vibrac

Well Known and Active Website User
VOC Member
Thanks Delboy that also perhaps explains why the Comet never used them but going by my GB29 dates either they were made but not used for 2 years or another make had the same gearbox architecture o_O
 

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