Burman B52 Gearbox help please

[Mick D]

Hi

If I had to speculate I'd suggest you have damaged one or both of the selector forks allowing one set of gear dogs to interfere with their associated cavities, this will feed back through the gear change cam barrel and on to the change indicator.
Careful strip down and clean will show the damage but you may need experience to identify it accurately, do you know anyone locally with experience?

What ever you do take loads of photos at every stage, point and angle.

Good Luck Mick

[nomisimon]

Hi Clive

Maybe it was a poor analogy. A short circuit in the dynamo armature would place an additional load on the engine, making the power available to drive the bike forwards much less. The extra mechanical resistance when turning the dynamo caused the inadequate method of securing the dynamo sprocket to the shaft taper, break free.

Simon

[nomisimon]

Hi Mick D.

Thanks...I always take loads of photos when I'm doing things like this.

The only person I know with experience is the person who didn't fit the key and special nut; I'm not sure I want to go down that road.

I'm pretty good with mechanical things and normally repair my own stuff, where sensible to do so. Every day is a school day...but what I really need is a Haynes type manual for a Burman B52 Gearbox

Simon

[Mick D]

Hi

Try this one:

http://archives.jampot.dk/technical/Tra ... _Bike).pdf

These gearboxes are very basic and any questions you may have reading the article will be resolved as you disassemble the box.

The Daganfly catalogue is also very useful:

https://www.draganfly.co.uk/ariel/4-str ... gb-gearbox

I'm cautious in saying that a GB box is essentially the same as a B52 - now running for cover

Regards Mick

[nomisimon]

Hi Mick

Thanks for that...now I will go and see what I can do...I may be gone a while.
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...but I'll come back and let you know what I find.

Cheers

Simon

[raffles]

Simon
an expanded view of the B52 Box is available from the Club
Tony

[SPRIDDLER]

...but what I really need is a Haynes type manual for a Burman B52 Gearbox

I've got one that covers everything.......

[nomisimon]

Haha...in an ideal world yes...I won't be the first or the last to have a senior moment, despite the best planning.

[nomisimon]

OK, I have the end cover off the gearbox, and have also checked the numbering on the box.

Contrary to my understanding, it is stamped GB26F55 which, according to the numbering sheet, is a June 1955 GB model gearbox, originally fitted to an AJS Model 20B!

With the cover ON, the gear indicator on the end of the selector cam shaft, moves in about an eighth of an inch and moves back when released; when released, there's a ticking noise like gears trying to mesh.

With the cover OFF, the cam can move further out and the gearbox locks...presumably two gears selected at once.

Should the selector cam move in and out so much...I would have thought not as it operates the selector forks. I can't see any parts damaged or missing there.

I note that the box contains a mix of grease and oil...is this right for the BG box?

I'd really appreciate some help...I know this must seem basic to some of you but I can't find detailed information on this box and don't want to split it if I don't need to.

Thanks

Simon

[Pharisee]

Two of my AMC bikes have Burman gearboxes and there is no appreciable end float on the selector cam on either box. That may well be your problem. If the selector cam can float about, then so can the selector forks, making gear selection very imprecise.