G: Gearbox (Single - Burman) Sleeve Gear

P

powella

Well Known and Active Forum User
Non-VOC Member
Only 22 days left before I leave the club , so here is a Gearbox horror for your enjoyment !!!.
Pics 1 and 2 show a well worm 4th gear pinion from a BAP box . The machine was actually a Panther 120 ( same box as a Comet ).
The heavy footed rider was trying to select top gear when suddenly he lost all drive and the noise "was like a Electric Hammer Drill "
Pics 3 and 4 show the mangled remains of the selectors.
Pic 5 shows that this was a VERY early box with ( probably ) internals to match.
 

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chankly bore

Well Known and Active Forum User
Non-VOC Member
As far as I can surmise, the earliest gearboxes, up to 1948, had no bushings on the layshaft to support the free running 28 and 34 tooth gears; i.e. steel on steel. Assuming your gearbox is original, this can be confirmed by the code on the inner cover which should begin with G42 then a month letter ("I" not used) followed by a year. All Comets and Meteor gearboxes I've seen have the bushed layshaft PR50-30BA. What is the code on this gearbox?
 
Pushrod Twin

Pushrod Twin

Well Known and Active Forum User
VOC Member
powella said:
Only 22 days left before I leave the club , so here is a Gearbox horror for your enjoyment !!!.
Pics 1 and 2 show a well worm 4th gear pinion from a BAP box . The machine was actually a Panther 120 ( same box as a Comet ).
The heavy footed rider was trying to select top gear when suddenly he lost all drive and the noise "was like a Electric Hammer Drill "
Pics 3 and 4 show the mangled remains of the selectors.
Pic 5 shows that this was a VERY early box with ( probably ) internals to match.
Click to expand...
What is the definition of a "very early" box? I think I see an oil drain plug in the bottom, am I wrong? IIRC, CP boxes used in AMC bikes had an oil drain & level plug from about 1950? I have a couple BAP Panther shells with oil drains indicating that they were post grease boxes. Vincent appears to have persevered with grease boxes until the bitter end while other manufacturers got on board with Burman's changing to oil. (or maybe the other manufacturers leaned on Burman to change???)
 
P

powella

Well Known and Active Forum User
Non-VOC Member
chankly bore said:
As far as I can surmise, the earliest gearboxes, up to 1948, had no bushings on the layshaft to support the free running 28 and 34 tooth gears; i.e. steel on steel. Assuming your gearbox is original, this can be confirmed by the code on the inner cover which should begin with G42 then a month letter ("I" not used) followed by a year. All Comets and Meteor gearboxes I've seen have the bushed layshaft PR50-30BA. What is the code on this gearbox?
Click to expand...
Hi
Thanks for your reply - can`t tell you the code `cos the box was rebuilt and has now gone.
The point I was tring to make was to show a worn out 33 tooth final drive cog with results.
Thanks Alan.
 
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