Hi I have a b33 1947 with the 1946/48 gearbox I have rebuilt the box several times now but every time it seems to tight like it nearly impossible to turn by hand it came to me in bits so not sure if I'm missing some shims or could it be something more serious if any one has got a diagram of the 1946/48 box would be great have looked on draganfly and searched the web but very little information on this gearbox many thanks clayton
BSA service sheet 302 may help.
Thanks for the diagram seem like all is correct
Is it poss that one of the roller bearings is not quite seating dead square, an right at end of it's recess? Just 1-1.5 mm out of square will load up the shaft, causing tightness. Bon chance.
I've come across this probem previously and one of the fixed gears on the mainshaft wasn't pressed on far enough. Could be that? All the best, Glenn
Could be the shifter forks are not sliding freely in the dogged wheel slots. Caused by:
-bent forks
-incorrect shimming of the shifter shaft
I have just rebuilt one of these! Mine would not change into 2nd. I took it out of the frame and stripped it completly.Took out the shafts and found some damage to the selector fork.This was in stock at Dragonfly. There was a slight burr on one shaft,which I dressed with a diamond file. The 2nd gear selector dog was not really free to glide up and down the shaft. However turning it round by 180 degrees freed it. Its called selective assembly. I then fitted each shaft into the box individually and checked the end float. I adjusted them all to .005 .I found the spacer on the selector fork shaft had been missed out by the previous owner. It works fine now. Good luck,you need to strip and rebuild the box numerous times to get it right. Happy to help if any of this seems a little vague.
Hi, if you check my post regarding zb32 gearbox on here there is a very detailed guide to stripping this gearbox. I found it very useful.Dennis.
Have you tried rebuilding it with 2 gaskets between the main casing and the intermediate one.
After another day playing with the gearbox still not right as soon as I put any torque on the casing bolts the box starts to get tight again just thinking would the 2 gaskets trick work unless I have a bent shaft maybe if I rotate the box backwards I have
noticed that the gears move across towards the casing cover
Does anyone know the thickness of the shims that go on the end of the 3 shaft before the end cover goes on as I was wondering if these could be to thick /thin maybe they were the only ones in the box with the gearbox bit on so may not be the right ones
Try building the gearbox without the shims.
Also, try building with just the main shaft the the main shaft plus selector shaft.
As mentioned avove, you need to shim each shaft seperately, one at a time, in the cases to get the end play for each shaft before you assemble them all together. If you don't use a gasket while you do this, aim for zero end float, which will then give you around 10 thou when the gasket is installed.
I did one of these boxes a year or so ago and they are pretty much the same as the later gearbox...except for a few details and that bloody awkward kickstarter spring!!!
Hi all finally got that 1946/48 gearbox sorted what a job but got there in the end working perfectly on the bench so can now get on with the rebuild thanks very much for all of your information and yes that bloody kickstart spring what a pain