My son's friend Matt who is 25 has made a marvellous job restoring an impressed Model 26 AJS and has done 90% of the work himself. I am doing my best to try and encourage the next generation into our hobby but one problem we have has moved him to the point of going back to modern bikes. The issue we have is that the gearbox seems to be missing 4th gear and we have had the front cover off twice and replaced all of the springs and pawl etc. Any suggestions would be very gratefully received. Cheers John T

John, I have limited Burman spares if necessary (kept for the Ariel 'box but may have some doubles.......)

email (option): sjmwdbikemad@aol.co.uk

Is it the CP box?

email (option): davmax@ntlworld.com

If its the Burman H type box, you are in for fun! I have had exactly the same problem with my Model 26 gearbox for the last three years and I have had the box to bits and back together again more times than I can remember. I think I've got it sorted now and I think the problem was the arm that holds the large ball bearing in the socket of the selector arm. It was just very slightly bent, which stopped the selector throwing the sliding gear for 4th all the way along the shaft, if that makes any sense? It's a really simple box inside and very straightforward to work on.

I agree, I've done a few of them, you can at least see what the box is doing in each gear. I've found them to be straightforward despite their reputation for being tricky to rebuild.

email (option): davmax@ntlworld.com

As I've stated a thousand times before to various CP box owners, all that usuall goes wrong when selection is a problem is this pin working loose in it's housing.

With the gearbox out the bike in first gear the clutch shaft will turn a lot faster than the cog driving the chain to the back wheel. press down slightly it will be in nuetrel .press down again it will be in second .The shaft then spins slower Than it did in first. press down again into third you will now have to mark both gears because there is not a lot of difference in the speed of the two cogs . Press down again into fourth and both cogs go round together. But i think your problem could be in the selector cog with the kickstart cover of the selector cog should be at a quarter to position there is a dot on top of the cog to set to this. then put on the gear selector the spot on this should mesh with the selector dot when you have done this take out the long bolt near the gear lever shaft put the case back on then you can put the bolt back in .

Of course you're right Billy. I just assumed it was indexed properly.

Thanks for all your answers. I should have clarified that this is a CP box and the dot on the selector cog is correctly lined up with the dot on the toothed quadrant . But still we have no fourth gear and this is even riding the bike up the road. Any more thoughts would be very welcome. Cheers John

I had actually got so fed up with it that I'd taken the original old H box out and swapped it for a CP, but now I've spotted the bent arm and sorted the old one, I'll swap it back over again. At least people know about the CP, when you ask them about lightweight Burman boxes before that, all you get is blank looks.

Hi

I am the guy who has been rebuilding this beast of a bike. When I first fitted the box it would only select 3rd & 4th, I then took the side of the gearbox off and I could select all gears although it would jump out of 3rd and 4th, this then got worst and I couldn’t select 4th at all and would still jump out of 3rd. When selecting 4th it would feel like I hit the limit/ extent of travel with no engagement from 4th at all.

I then replaced all the parts John has mentioned above and lined the two dots up, put it all back together and although have a much more positive gear change it still does not select 4th and feels like it has reached the extent of its travel.

A query I have above the root cause of the issue is, if I was slightly out on the lining up of marks or my 9 O’clock position was closer to 10 O’clock or 8 O'clock would this cause such problems as described above ? (I don’t believe it is as far out as 10 or 8 O’clock)

One last thing I noticed is when doing the nut up that stops the gear selector coming off, if I did it too tight it would click into gear without moving the selector itself, am I missing something ?

Don't give up on it Matt, I hope someone can help you with your problem. The Model 26 is a lovely bike and will always attract a crowd wherever you park it. Does yours have the chrome tank and twin exhausts?

It has a Green Tank ( along with a lot of other green parts )With a sprinkle of chrome including Chrome twin high pipes which make a lovely sound. Here is a picture with the faulty gearbox in ;)

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Very smart indeed, this is the first militarised one I've seen and it certainly suits it. I think the War Office did take a few for evaluation, but never took them in large numbers, perhaps only a couple or so I think? There is that famous photo of the giant British soldier sat on one I think too? It did the rounds on the forum a few months ago.

Yes I have seen that photo. I have another one of a guy sitting on one with twin high pipes, that is the picture we have used to take detail and part placement from. Both John and I were surprised at how many parts differ from a Matchless G3.

Bill, sorry to disagree with you but I can prove to you that the MOD took at least 1,300 AJS,s but these were not all Model 26's. Interestingly there were also some Model 26/H 's which had the Matchless heavy weight forks. I have quite a few photos of WD AJ's .Cheers John

Fair enough John, I'm glad to hear it and if you read my post again you'll see that I wasn't exactly being the worlds authority on military use of AJS, far from it, I thought I'd proven quite nicely that I didn't know what I was talking about! Just out of interest, do you know how many of the 1300 were Model 26 machines? I wish I'd painted mine green for a start, it would have saved a great deal of messing about getting the tank chromed.

Were these impressed bikes John? I see only a handful delivered under a WO contract.

Here are a couple of impressed bikes.

email (option): ronpier@talk21.com

I'm pretty sure I could sort it. I run all the gearboxes I do on my lathe and try the selection in every gear, it's surprising that boxes that seem to select poorly on the bench but when you put them on the lathe with the mainshaft in the chuck they can actually change gear quite well. If you are at your wits end you could send it up to me
Dave

email (option): davmax@ntlworld.com

Ron, yes I should have clarified that they were impresses rather than supplied under official WD contract number. However, there were sufficient supplied to warrant their own parts list.. There were a dozen 1939 AJS's supplied together with 1,306 1940 models. To answer the question there were 589 Model 26's, 65 model 26/H's and 40 model 26/L's supplied.i have wondered that this is a lot of bikes to be in stock at the factory? Cheers John

Yes I have a copy of that parts list John. I hope Mat gets the box sorted. Good to see those young fellows so interested!!

Here is another one that came my way......And the giant. Ron

email (option): ronpier@talk21.com

Problem Solved !!!

This Sunday I stripped the gearbox down to component form, removed all the old grease checked each component for wear and then using a spare gearbox I made a hybrid box of the best part from each. So with a mashed selector found in the box on the AJS, the better condition one was installed from the spare box. Bolted the box back together, checked I had 4 gears. No 4th gear, same problem as before.

So I then stripped the gearbox again for forth examination, with it all back down to its components again and some umming and Arghing between John and I, John with a new 4th Gear in hand and playing with the selector gear in this 4th gear had a light bulb moment. The bush inside this gear maybe sticking out too far.

When I looked inside the box I discovered that the bush was not protruding a little but a lot, preventing the selector gear from getting anywhere near selecting 4th, so with a little persuasion with an Irish spanner the bush was nudged back into place. And after putting it all back together for the second time and the selector mechanism in and out a few times during the process as I forgot to put bits back in. It is all back together shifts are very direct and super smooth.

So anyway my rates are negotiable @ £100 p/h and I provide no Guarantees

Good to hear you found the problem...

You always will if you stick at it long enough and the 'silver lining' is that you learn something about the bike along the way....Ian

email (option): ian@wright52.plus.com

That's great news, I'm really glad to hear it's fixed. 9 out of 10 times it will be something small that can be fixed by hitting it hard enough!