XBAPH parts

chankly bore

Well Known and Active Forum User
Non-VOC Member
The standard post-war gearbox, at least all the standard "BA" variants I've seen, had top-hat bushes on the layshafts, cracking of the case was not such a problem with ordinary road use. The Norton/A.M.C. gearboxes seem a little more prone to this weakness, especially with the standard drive side layshaft bearing fitted. I've got to admit, though that the 61207 bearing was a sublime drawing- office dodge!
 

Vincent Brake

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VOC Member
Took one apart yesterday eve,
indeed the gear cluster from a post war fits in a prewar box, and ive got all gears now. :D In prestine condition. Only to machine some new bushes from Ph bronze, or order at VOC if oillite, get all leaks out of the box, and fill with normal SAE 90 oil
Thanx
 

greg brillus

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VOC Member
The hardest one is where the clutch main shaft comes out through the output shaft...............Too small to fit a seal............Easiest way might be to make a longer sprocket nut that overhangs the output shaft and fit a slim seal there, not much room though.
 

Vincent Brake

Well Known and Active Forum User
VOC Member
or use a V seal, and machine the face of the sprocket dead nice n smooth.
with an O ring inside, maybe its lasts a sprocket life......

and nessecary tooooo, as the groove in the main shaft needs to get the oil in the far bronze bush.
 

chankly bore

Well Known and Active Forum User
Non-VOC Member
Took one apart yesterday eve,
indeed the gear cluster from a post war fits in a prewar box, and ive got all gears now. :D In prestine condition. Only to machine some new bushes from Ph bronze, or order at VOC if oillite, get all leaks out of the box, and fill with normal SAE 90 oil
Thanx
The output sleeve bushes must be Oilite. The top-hat bushes for the layshaft must be Oilite. Some?? pre-war and early post-war boxes had no bushes for the free running first (34 teeth) and second (28 teeth) layshaft gears. All the original post-war Comet boxes I have examined had phosphor-bronze bushes for these gears. This material is O.K. in this position because these two bushes are lubricated by 1/8" cross-drillings in the two gears. Do check that the drillings are clear, though. They are often occluded with Cro-Magnon deposits of hardened lubricant. They are another reason to use modern semi-fluid lubricant rather than grease. A very good engineer once thought it smarter to make the top-hat bushes in bronze. They seized on the layshaft at 60 m.p.h. Very nasty. Fortunately gearbox and rider survived.
 
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