CP gearbox

[david.anderson]

I have purchased a bike that came with a dismantled cp gearbox. Supposed to be all there but the ks ratchet and pawl are 6 spline and not 4 spline (missing 3/16 rollers and detent spring. I have never seen a CP before so I have a couple of questions.
I have assembled the gears on the shafts in what appears to be how they go

When the mainshaft is put in the box and pushed to the sleeve gear the 3rd gear extends well beyond the case

If the mainshaft cluster is assembled in the box, there is a large gap between the sleeve gear and the clutch roller flange on the mainshaft (whereas there is only a small clearance with a BA box). Is that gap correct for a CP.

There is a large amount of end play .090” to the mainshaft when assembled, however I have temporary assembled with a sloppy on the shaft fitting BA ratchet and pawl which may be a different height. What is the correct end float, for when I get the correct parts.

thanks
David

[Roger Gwynn]

The C box is the same as the BA box except for the size of the shafts, casing, gears and filler plug, all the gear change and k/start mechanism is the same. The end float should be 1/64, ie. minimal but enough to know that the bearings are not loaded.
Your layshaft at least is 1950 or later as denoted by the groove near the speedo gear that indicates the modified ratio for chronometric speedos.
I cannot see anything obviously wrong with the parts but but the C box was used on a lot of other makes so there are other mainshaft lengths although that should not affect the fit of the gears as they should be the same, other than tooth numbers.

[david.anderson]

thankyou Roger.
Am I correct in assuming that the gap between the mainshaft flange and the sleeve gear should be minimal as it is with a BA.
David

[Roger Gwynn]

I have measured one I have in the shed at about 3/16" or a little more, not far off what you have by the looks of it.

[nevhunter]

I have a Never disassembled W/NG box with Low miles I can check accurately for dimensions and end float, I'll get back to you tomorrow with Luck. The Location of the Mainshaft is achieved a t the Kickstart end. Nev

[nevhunter]

The Gap was 7 mm and the end float almost zero. Another I have fully rebuilt was 5 mm. all from W/NG's. I'd go for what Roger suggests a loose 3/16ths of an inch. The Main thing is the top Gear engages fully and the sleeve gear bush is not Loose or you risk dropping out of top gear and having Primary chain tensioning issues. Nev

[david.anderson]

Thanks
Clearly a lot more gap than a BA, so I will assemble it.
David

[nevhunter]

You should get an indication where the sleeve bush has been running, so assemble all the gears with the selectors in the Main case and see how it aligns in all the gears. It can be done with the Gearcase in the bike. Just Make sure any of the 1/8 x 1/8 rollers don't fall out. Nev

[Pete.Silson]

I think you have the two gears A and B in your first picture reversed. A is the layshaft 3rd gear (23T) and B is the layshaft output gear (20T).

Pete

[dave.owen]

Pairs of gears(opposites) always should add up to the same number of teeth

Dave