AJS & Matchless Owners Club

I'm asking someone with a bit more knowledge and myself for some information on an AJS 39/26. The gearbox number is CPB 29717, is this oil filled or grease please? If grease what type. Also one of the exhaust ports is blanked off, is this normal on the said model if it has a twin port head? Many thanks.
Tolly.

I'm out of my depth with that year but I'll have a go. This seems to be the Owners Manual for the 39/26 which specifies grease on pages 10, 16 and 56:

http://archives.jampot.dk/book/Owners_m ... manual.pdf

I may well be completely wrong but there's naff all on t' telly and I'm sitting up to keep my son's (he's on hol in Australia ) dog company before all the fireworks hell breaks out.

The first bike I rode was a 37/26. back in 1956. That bike came the left hand port blanked off with a bit of tin bent over the spigot and clamped on the a cooling ring. The owner said many bikes only have a RH exhaust. Most exhaust systems that were about were all R hand. So money was saved by blanking it off. I Told the old bot across the road, I would like to have like have it as a twin. He said bring it round I have something I can make a left hand exhaust with. He fitted some sort of metal flexi hose on the make a pipe, plus and old silencer. Nothing matched the RH side, but I got a twin port. ( 2.30 am and I've just finished entertaining with music , a packed pub for New Years Eve. )

SPRIDDLER wrote:I'm out of my depth with that year but I'll have a go. This seems to be the Owners Manual for the 39/26 which specifies grease on pages 10, 16 and 56:

http://archives.jampot.dk/book/Owners_m ... manual.pdf

I may well be completely wrong but there's naff all on t' telly and I'm sitting up to keep my son's (he's on hol in Australia ) dog company before all the fireworks hell breaks out.

Thanks Spriddler, I had looked through that but was not convinced as there looks to be oil in the gearbox. I think if it was designed for grease that's what will go in.

Hope your sons dog wasn't too disturbed.

Rob Harknett wrote:The first bike I rode was a 37/26. back in 1956. That bike came the left hand port blanked off with a bit of tin bent over the spigot and clamped on the a cooling ring. The owner said many bikes only have a RH exhaust. Most exhaust systems that were about were all R hand. So money was saved by blanking it off. I Told the old bot across the road, I would like to have like have it as a twin. He said bring it round I have something I can make a left hand exhaust with. He fitted some sort of metal flexi hose on the make a pipe, plus and old silencer. Nothing matched the RH side, but I got a twin port. ( 2.30 am and I've just finished entertaining with music , a packed pub for New Years Eve. )

Thanks Rob, the left port does seem to have been professionally blanked off so it may be as well just to replace the r/h exhaust. Can you remember if it made much difference by opening up the other port? Do you think there is any advantage?

Many thanks, Tolly

I some how do not think there was an advantage in having twin ports. I think twin ports were a trend / fashion of the era. Perhaps less advantage, as the tuned engine models of the era, also AJS Silver Streak models, had only single port heads.
Grease in the gearbox I am sure would be correct, although adding just a little oil was hinted at in manuals. To make gear change a little easier. Grease taking time to warm up etc. Expect a little leakage if adding that egg cup full of oil. Expect gear change will not be as good as later models. As gear boxes were improved upon. You get used to having to cox these old gear boxes in gear. When changing down I often have to go down 2 gears then up one. They seem to work better going up, than they do down the gears.

That Owners Manual refers to it as a 'Twin port' which it obviously is/was. Perhaps a P.O. blanked it off because the l/h pipe got in the way of sidecar fittings..........
There are three types of g/box mentioned in the manual and all are shown as using grease. Yours is a 'CP' 'box based upon the stamped number that you quoted.
As Rob mentioned, twin ports seem to have been a fashion thing for singles in that period. When I was 13 I bought an engine from a 1936 New Imperial 250 from a junk shop with my paper round money and imagined that it was a racer because of its twin ports.

Yes Tolly, the dog was fine and bloomin' well slept all through the whooshes and bangs that kept me awake in spite of a large monograde Calvados

Hi Tolly

As stated above originally the gearbox would have been a grease one, do you have a grease nipple on the top of the outer cover this is usually a sure indication, it is possible to use the 1948 on drive side lip seal and to improve the seals on the shafts in the outer covers to make them more oil tight, personally I use self levelling grease in mine if too much starts coming out I top up with normal grease. ITMA used to recommend adding some graphite but I have never done this.

Thanks very much for the info chaps, happy new year to you all.