Sleeve gear - number of teeth

If you find and fit a 23t sleeve gear.........this in effect converts your gearbox to almost an AMC 2 version. This was the gearbox fitted to the Norton twins from around 1961 onwards.

The advantage of this change being that the first 3 gears are all raised slighly. The biggest benfit being to narrow down the previous huge jump between 3rd and top.

OK.....first is a little higher and this might stop any previous tyre rubber melting, front wheel lifting launches but the chances are unless your engine is well down on power and you have a 1 in 5 garage drive slope, you will not notice.

Previously Dan Field wrote:

Thanks Philip! Both AN and RGM have the 23 tooth sleeve gear.

Hi Dan,

Sorry I'm a bit late coming back with this, but I guess you realise you will need a 19 tooth layshaft gear to match. It might be worth looking out for a good second hand24T. If you do decide to change the ratios, calculate the speed in each gear and check if this suits your riding.

Regards, Richard.

See attachment for cogs inside standard Norton AMC type of gearboxes.

My understanding is that the radius and profile of both the 23 and 24 tooth sleeve gear is such that either will mesh correctly with its opposite 18 tooth gear on the layshaft. Many AJS and Matchless bikes had a 23 tooth sleeve output gear as standard inside their version of the AMC gearbox.

The second gear on the Norton AMC 2 box Layshaft also dropped down a tooth to 20 in total. Once again the pitch circle was maintained on the the replacement part which enabled it to correctly mesh with the opposite mainshaft gear.

Hi Dan/ Phil,

Sorry I was thinking of the earlier 'boxes , AMC2 is too new for me! I should have realised as Norton done the same thing with the Inter bottom gear as far back as 1935.

Richard.

P.S. Phil, thanks for the ratios chart.

Previously Dan Field wrote:

im rebuilding my gearbox (AMC) and am thinking about replacing the 4th gear on the layshaft and sleeve gear ( despite all my efforts the layshaft gear is too tight a fit on the shaft and isnât in brilliant condition anyway). The layshaft gear has 18t and the sleeve gear has 24t, I canât see a replacement 24t gear on the RGM or AN site, are they just not available anymore?

cheers

Dan

hello dan are you real desperate for a 24 tooth sleeve gear as I have a new old stock spare for a 1954 dominator laydown gear box yours anna j