Box of bits assembly of 1955 G80S

[RobC_LAPSED]

Thanks for your tip on the thin headed bolt. I've just got the pieces in loose at the moment to see what goes where. It was 50/50 which way I may have put that bolt in first! I did wonder why this one was not a stud! Thanks for your eagle eyes on that one. It also showed I didn't have the long chaincase stud so have ordered that too with its long nut etc.

On another issue, I'm replacing the head stock bearings. Luckily in the boxes of bits was a new complete set, unused and 40 year old! The top and bottom yoke cups are different profiles, I can just copy which way around they were installed, i.e. the one with the chamfer on the bottom yoke, but then it had one of the rounded frame cups in the top yoke! I'm assuming the bottom one is right and the square cross section one goes in the top yoke? It has a very slightly smaller ID so it would probably be difficult to get it on the bottom yoke! I don't want to get myself a reputation of getting bits ass about face though I've been searching the forum and cant find a description or picture. The parts book diags are not clear enough for me, other than the part numbers.
Rob.

[dave16mct]

Yes you have those the right way round. (The parts list does tell you.)
Dave.

[robcurrie]

Might come in handy for a quiz one day....

[quizmaster]

[Invicta]

Hi
I am in a similar position to Rob with a box of bits. I found the archive pictures very helpful, but it did not list a 1949 model 18 . I have printed off the 1946 AJS 500 and the 1952 AJS rigid pictures , which I am sure will help to identify the location of some of the spacers and studs. Does anyone know if there is a similar drawing anywhere for a 1949 rigid. I understand that the 1949 model 18 had quite a few minor differences from other years.
Dave

[RobC_LAPSED]

Hi Dave,
Looking at the engine mounts doc, the rear engine plate seems to have changed substantially between the 48 500 Matchless (like the 46 AJS) and the 1950 plate (similar to the 52 AJS). I guess you will know which type you have.
In my book on the history of Matchless/AJS it says the pivoted-fork rear suspension was introduced in 1949 and there were also several engine changes on the 18/G80 then, including a new head, rocker cover and barrel. It also says for 1949 that in theory, it was possible to convert a rigid frame to rear sprung. I'm guessing that these changes is what caused the plates to change between the 48 and 50 ones shown? I'm sure others will put me right on this if I'm barking up the wrong tree?
If I'm right then I'm guessing yours will be similar to either the 48 or 50 Matchless?
Rob

[dave16mct]

The thread is getting confusing now talking about other years and rigid frames etc. '49 had a new frame with different geometry to '48 so the engine plates are different. The AJS plates are different to Matchless plates at the time as the mag position was different. If we can keep to '55 questions it'll be easier! Invicta needs to start his own new thread.
Dave.

[RobC_LAPSED]

Frame1.jpg

I've got the frame loosely together and awaiting a couple more parts before I can get the forks fully back together and headstock in. Can anyone see any other mistakes with the frame assembly? I have turned that shallow head bolt around now!

Before I have a go at putting the engine in I thought I'd have a look at it. The guy I bought this from said he had rebuilt the engine. I've got one of those endoscope camera's (great little ebay gadget for all sorts), so I had a look down the barrel. The piston is very clean and got +40 on it, so it looks like it's had a rebuild. It's also got new pushrod tubes.
The gearbox is another matter! From my reading it should be a Burman B52 (bombed out?) It's been apart before and got no oil in it. I can turn it now with the main shaft or kick-start but I cant get the gear selector to do any more than a small push down with spring return. I cant get it to change gears. Does this sound like a full strip down?
Rob

[Mick D]

Hi

You need to rotate the shafts in the gearbox, (spin the sprocket), as you apply firm and steady pressure to the gear lever. If it doesn't change then it will need a strip down, the gearbox is easily stripped and requires no special tools unless you need to remove the sleeve gear.

Regards Mick

[dave16mct]

Looking good. You've made a good start. The gearbox adjuster should be on the other side. The gearbox may be ok. They're very robust. Spin the mainshaft when you're trying to change gear. Easy to strip down now if you want to be sure. You'll be sick if it's all together and oil leaks from the mainshaft seal.
Dave