Primary Chain Adjuster Confusion

[Andy E]

Hello. I am trying to sort the correct primary chain adjuster set up for my 1956 AJS 16ms. The current setup is wrong and uses a transverse crosshead fitted between the engine plates. This uses 5/16" spigots on each end to fit into the 3/8" holes in the engine plates that would normally be used to bolt the correct crosshead to the left side engine plate. An eye bolt passes through the centre of this and the head of it pushes against the back of the gearbox top lug. There is no need of an eye bolt.

The confusion arises when I consult the 1956 Spares listing and 1956 Manual. The manual clearly shows a crosshead bolted to the left engine plate with a normal bolt threaded into it and secured with a locknut. This bolt again is shown pushing against the top gearbox lug.

The parts listing however lists crosshead part number 022504 and eye bolt 022595. Again, there is no need for an eye bolt. The AMOC spares website has no illustration for part number 022595 so I am not able to determine if this part number really is an eye bolt. The description does though state "Primary Chain Adjuster Eye Bolt B52 Gearbox"

I would like to fit the correct arrangement. From searching the forum I see that some bikes are fitted with an adjuster fitted outboard of the right side engine plate and that these do use an eye bolt and presumably a longer gearbox top mounting bolt.

Can anyone let me know the correct setup?

[Rob Harknett]

Parts list should show the correct parts. Be sure you use the correct year manual. Note publication date is the nearest beyond your year bike.
http://archives.jampot.dk/book/Workshop ... dition.pdf
Beware of old artwork. Don't forget, tightening the primary chain will loosen the rear chain. So end by doing the rear chain and brake adjustment. Dont forget to loosen the brake anchor adjust brake and re tighten.
http://archives.jampot.dk/book/Owners_m ... models.pdf

[Andy E]

Hi Rob. Do you mean that I should be looking at the 1957 parts listing for my 1956 bike? I have just looked at the 1957 parts listing and is does list a different part number for the adjuster bolt, but the description is still "Eye Bolt". The AMOC spares website though has the description for part number 022869 as "Bolt Gearbox Adjusting 1957-1964", but there is no photo of the part. The 1957 bike seems to have the AMC gearbox whereas my bike has the Burman B52.

[56G80S]

Personally, my 56G80S came with an AMC box. I replaced that with a B52 correct for year and subsequently refitted the AMC.

There's no eyebolt required for the AMC box. The thing that stops slippage (something I struggled with in the early days before fitting the B52) is the bolt through the cross piece between the engine plates and with the head bearing onto the top mounting bolt through the cut out in the gearbox casting.

When I bought my Matchless with AMC box there was an eyebolt arrangement in place instead of the "correct" arrangement. I used some of this eybolt stuff when fitting the B52; I worried less about the "originality" than ensuring that the gearbox didn't slip. I also acquired some additional eyebolt parts and mixed and matched until I had something that worked. I believe (and others more knowledgeable will correct this) that there are eyebolt arrangements added to specific competition machines which may differ from the setup for road machines.

Not much help but at least you know you're not the only one!

Johnny B

PS When I refitted the AMC box I discarded eyebolts and the used the correct bolt through crosshead approach which worked fine but is not appropriate for a B52.

[ajscomboman]

I would suggest that the parts manual is wrong in the description. 022595 is only a plain bolt not an eyebolt.

Parts for adjuster for 56

022595 x 1 crosshead bolt, 022504 x 1 crosshead, 000402 x 1 bolt fixing crosshead to engine plate, 000004 x 1 nut for crosshead adjuster bolt, 000010 x 1 washer for crosshead adjuster nut

Before you order 022595 just let me check the stock at Kettering tomorrow to make sure what we have is correct for 022595, if it's not I'll have to get it sorted.

[ajsph]

the system shown in the 56 manual first appears in the 59 spares list, the photos show the parts I use on my 56 twin, only the crosshead bolt is different from the parts used on the single
Poul

DSC01879_1.jpg

[ajscomboman]

Whilst not correct for 56 Poul it can be used naturally and quite honestly it's easier to adjust the g/box using that setup.

[ajsph]

Correct Rob, I have the system shown in the 56 manual on my 56 model 30, it is not an easy job to adjust the gearbox, particularly on a Twin, so I have changed the adjusting system on my other bikes.
Poul

[markwhitelock]

I have this same set up on my 1956 G80, it makes adjusting the primary chain straightforward enough.

[Rob Harknett]

Hi Rob. Do you mean that I should be looking at the 1957 parts listing for my 1956 bike? I have just looked at the 1957 parts listing and is does list a different part number for the adjuster bolt, but the description is still "Eye Bolt". The AMOC spares website though has the description for part number 022869 as "Bolt Gearbox Adjusting 1957-1964", but there is no photo of the part. The 1957 bike seems to have the AMC gearbox whereas my bike has the Burman B52.

Parts list must be correct year. Workshop manual as near as possible. The manual I gave a link for was published 1957. A later one would say it cover's eg 1950 to 1959, but have very little that relates to the earlier years. If your bike is not correct, you may need parts lists for the various parts. If what you have works OK keep as it is or start replacing large lumps that are not correct.