Can you identify these Ariel gearboxes?

[Dave.Barkshire]

I have some gearboxes in the garage and was wondering exactly what they're from.

So far as I know the first two are pre war but I don't know the difference between a PBD and PBL. The last one I guess is from 1951? There are some photos below...

The stamped numbers are...
Gearbox 1 : XIC PBD 19449
Gearbox 2 : XIC PBL 68200
Gearbox 3 : G107 B51

[brenton.roy]

Hi Dave,
Using Roger Gwynn's article in the knowledgebase,
G107 51 is a 1951 single or twin BA
The CP box with clutch, (if the clutch arm is original) is late pre war or post war lightweight - or I think early KG / KH.
Not that it means much, but I think mid 30's clutch arms were solid, not pressed. I don't think the last two digits means anything re the year. I don't know about the last letter.
The article suggests that chronometric speedo drive gears from 1948 have a groove to separate them from PA drive gears. As far as I know, this is all that would mark the CP's for a particular era.
Brenton

[Dave.Barkshire]

Thanks Brenton. I have been doing a bit of poking around and there are a few snippets of Burman info but I will pick some people's brains further when/if the Red Ariels book goes ahead.

[brenton.roy]

I hope when rather than if...

[eric.delegrange]

Hi,
For my 1951 VCH 500, I want a G107 gearbox,
Did you sell yours ?
Thank in advance
Eric

[paul.jameson]

The postwar gearboxes can be identified by type - the G107 number against the Draganfly list. Then A 51 means it was made in January 1951, B 51 means it was made in February 1951, etc., but the letter I wasn't used in this sequence.

Prewar is more difficult. The basic information is the CPBD or CPBL sequence, followed by the number. I am pretty sure the numbers are sequential throughout the thirties and the preceeding letters simply tell us the type of gearbox. At this point I must go to the BA box because the 1 prefix on a BA box means it is for a single whereas the 2 prefix means it is for a Square Four and so has the offset lugs on the main shell. I suspect the X means a needle roller clutch rather than a 1/4 x 1/4 roller clutch but I may be wrong on this. So going back to the boxes in question, the X1CPB* means a singles box with needle roller clutch. I have no idea what the D or L mean, but some BA boxes have an H so H might be high, L might be low and D might be dunno. This is very much work in progress and a month ago the only thing I could have said was that I thought the numbers were sequential throughout the thirties. The problem is finding bikes of known date with known correct gearbox numbers. No doubt the information can be extracted from the Machine register in the Club Archives but I was always too busy dealing with the dating queries to be able to find time for research such as this.

[fpassmore]

The suffixes information I have found is this.

[Vincent.vanGinneke]

I think BA boxes have the grease filler cap on the right side of the main housing when looking from the gearchange side.
CP boxes have them to the left side of the main casing.
The one in the picture on the left looks prewar to me as it has a more pronounced 'step' in the front cover where the gearchange mechanism sits behind.
Both 350cc boxes ?
Gearbox No.3 is indeed a Feb. '51 BA, but I cant see the filler cap from this point of view.

[simon.holyfield]

Anyone know when the acorn nuts appeared, to hold the kick start case on?

[john.whiting]

Mr Passmore has revealed all,Burman wise.B is for balloon tyre chainline,which is the one I could not figure out.All is revealed to the true believer.Incidentally,all pivot mounted gearboxes paid 1/6 royalty to Walter Moore the designer of the original cammy Norton,who patented the idea in 1924.The patent ran to 1941.BSA refused to pay and all BSA boxes had two slots in the plates for adjustment,as a cunning way to get around the patent while still using the idea of thrubolts.Regards John.