Greetings!

My CP gearbox has this number - 8CPBL42885.
What will be the year of manufacture?
Please do let me know if this will have 12 small rollers on the layshaft.
Your replies will be extremely helpful.

Regards
Pratap

email (option): prataphenry@gmail.com

Pratap,

Can't help you with the year of manufacture but it is definately a WD gearbox because of the prefix and the letter L (Low gearing)
Which rollers do you mean? The layshaft has a bronze bush on both sides, no rollers.
Do you mean the rollers on the camshaft as mentioned in the maintenance manual?
This is also a bit of a questionmark to me, all the parts lists I have mention the 45-C-3 camshaft so it is not clear to me when this early camshaft 45-C-2 was used.
My gearbox has number 8CPBL 38539 and has no rollers on the camshaft.




Regards,
Peter

Thanks so much Peter, One last question. When i tighten the inner cover of the gearbox to the housing (4 studs) the gear shafts are not moving. However when I loosen the nuts a bit they seem to work fine. Does this have anything to do witt the thickness of the gasket in between?

Regards
Pratap

email (option): prataphenry@gmail.com

If would try to put the gearbox in gear with the nuts loosened a bit and then tighten the nuts, if the mainshaft and layshaft spin freely without too much axial play the tickness of the gasket should be OK.
If you can't change gears after that because the camshaft doesn't move I think the fault lies in the collar thickness of the bronze bushes of the camshaft.

Regards,
Peter

Just try a thicker inner gasket first.

Thank you so much Peter/Douglas, the gearbox worked fine.

Regards
Pratap

email (option): prataphenry@gmail.com

Hi there what will be the thickness of the gasket used here. Im breaking my head and in my case it is the neutral which doesnt shift. :( - J.M

email (option): johnmatthew04@gmail.com

Hello Pratap,

The Burman CP gearboxes all have a number that is made up like this:
- CP prefix
- E prefix for Enfield, or BL prefix for Bottom Low as used on Matchless and Ariel motorcycles
- gearbox number

There was only one gearbox number sequence, that ran from 101 (I guess...?) until at least 94000. Royal Enfield has made a contract with Burman gearboxes, this contract was made from July 1942 until October 1943. During this contract the gearbox numbers ran up from approximately 500 until approximately 93000. Your number is somewhere in the middle of that series, so I guess it must have been made somewhere in early 1943.

Regards,
Jan

email (option): wd.register@gmail.com

John,

The ones I used are 0,25mm thick (0,01").
But I wonder if in the grease lubricated pre 1948 boxes a gasket was originally fitted, in the parts list and the maintenance manual a gasket is not mentioned.

Regards,
Peter

gaskets all round on the grease boxes but not thick ones.

Hi, I also have more or less the same problem. I can easily get into 1st, Neutral but when I try to shift to 2nd there is a jolt and the wheel moves like in neutral but with a lot of noise. Any tips to get this sorted, everything on the box is new. is it advisable to use washers on the inside of layshaft and mainshaft?

J.M

If no washer were originally fitted there is no point.
these boxes are fool proof, so you have not assembled it correctly or have used a wrong part.
The clue is in "..everything in the box is new...."

just this mean bearings or gear cluster?

email (option): deadsheds@yahoo.com

Hi Ken, I totally agree. New bushes, new studs new seals. There is one small thing that I am missing. Tried gaskets of 3 different thickness. Either neutral is a problem or the 2nd gear. Do you have any pictures of a CP Burman gearbox?

J.M

I doubt gaskets are the root of this problem.

I have some Burman info will dig it out later.

start with the simplest thing, did you time it right? O to O?

a wild card being you have perhaps interchanged the two gears that look similar?.

email (option): deadsheds@yahoo.com

Yes thats where the trouble is I think, how do I differentiate between the 2 gears? I think I am confused between 3rd gear foe mainshaft - 29 teeth and second gear on layshaft - 27 teeth. please let me know.
J.M

Hi John,

This is the only picture I have of the CP gears:



Regards,
Peter

All the Burman information is available on here including exploded views. The site is http://archives.jampot.dk/

email (option): davmax@ntlworld.com

Many thanks to you Peter. I will try fitting this going by the pic that you sent me. One doubt that I may have is about the layshaft. Can the layshaft be used either ways? In other words if we cut this from the middle, will botht he halves be similar? :(
Can the sliding clutch (Black Arrow) be loaded from either ends of the layshaft (Marked 1 and 2 in red). In mine I can load this from one end only.
I also have marked the gear wheels. Hope I got them right.


J.M

Hi John,

No, the layshaft can't be used either ways.
The gears with 21 and 18 teeth on the layshaft have a different width so the length of the splines on the layshaft differs.
The sliding clutch can normally be loaded from both sides.

You have marked the gears OK but I think it is not possible to assemble the gear clusters wrong.
You can't put the gears wrong on the mainshaft, if the gears on the layshaft are assembled incorrectly this will be noticed directly when both gear clusters are hold against each other (the way I took the picture)and in that case the gear clusters won't fit into the gearbox shell.

Regards,
Peter

Hi Peter. Thank you thank you. Sure that the sliding clutch can be loaded from both sides?. I can load it only from one end. i.e from end 1 in pic. It gets stuck and doesnt fall through the other end. However the gear with 32 teeth holds it in place and i think there might not be a prob. Or was this the cause of all my trouble?
J.M

Hi John,

Yes I am sure it can be loaded from both sides, just tried it on a spare layshaft and sliding clutch.
Probably the splines for the sliding clutch is damaged, also check the mainshaft and layshaft for straightness, my experience is that these shafts are very hard and often pieces of the splines have broken off.
It is possible that such a piece has bend the shafts when coming between the gears.

Have a look at this tittle (page 16/17), some problems with the CP box are mentioned:
http://archives.jampot.dk/Book/Workshop_manuals/Matchless_Motorcycles_1939-1955.pdf

Regards,
Peter

Hello Peter. One doubt and hopefully the last. I am loading the gear selector fork with the O in the gear shaft at 9 O clock position. If the shaft is at 9 O clock does it mean that the bike is in neutral. Or is it just a reference.
J.M

Hello John,

It is just a reference, the gearbox is not in neutral.

Regards,
Peter

I can't emphasize that this pin be a solid press fit in the selector housing. Or you will get missed gears.