AJS & Matchless Owners Club

I attempted to remove the timing gear pinion on my 1949 model 18 , as I want to split the crank cases to check the state of the bearings. I ground down and filed the claws of a sprocket puller to fit under it . With a small G clamp across the legs to stop it slipping off, the legs of the puller simply bent. I was applying a lot of pressure but the pinion did not budge. Even a sharp tap on the end of the puller with a hammer did nothing but jump the puller off. I bit the bullet and ordered the special puller from the club spares scheme. Just how hard are these pinions to pull off their taper ?
The face of the inlet tappet showes no sign of wear, but the exhaust tappet face is worn into a slight depression. Is this something to be concerned about? To repace it will apparently require the use of another specialist tool. If such a thing is still available.

If the pinion and key were in good condition when assembled there shouldn't be a severe amount of pressure required to pop it off it's shaft. If considerable force is required then I suspect the key is jamming the pinion on. You'll bust the new tool if too much force is applied, therefore it might be more prudent to split the timing pinion and but a new one along with a new key. Ask me how I know this?

You can split the cases without removing the pinion.

Harry44 wrote: ↑Thu Feb 15, 2024 1:31 pm You can split the cases without removing the pinion.

Not on a 49 model you can't. They have the smaller bush and it won't pass through like the later models. Pinion HAS to come off.

I had another go this afternoon with the sprocket puller and a bit of heat from the ocyaceteline torch, as the special removal tool did not arrive today. Still no joy. How did you split the pinion? in case I have to resort to that in order to get it off.

Cut a groove between the teeth with a Dremel or similar tool and then tap it gently but firm with a hammer and small cold chisel it should be enough to crack the hardened pinion open. If not grind out a bit deeper and try again. Eventually it will surrender I promise you.

ajscomboman wrote: ↑Thu Feb 15, 2024 4:12 pm

Harry44 wrote: ↑Thu Feb 15, 2024 1:31 pm You can split the cases without removing the pinion.

Not on a 49 model you can't. They have the smaller bush and it won't pass through like the later models. Pinion HAS to come off.

Sorry my mistake

The special removel tool arrived, but as somone pointed out in another thread there is not a big enough gap under the pinion to get it in. The author of that post did say it might need a few taps to get it under. An understatement if ever there was one. The foot of the extracor tool was 10 thou thicker than the gap. I did not want to weaken it by grinding any off, as someone did mention they have been known to break if too much force is aplied. UIsing a mild steel drift and some determined hammering I managed to get it under the pinion and a fair bit of pressure on the bolt and off it popped.Now to get the exhaust tappet block out.

am in the process of splitting the crankcase also my hoj is a 1953 model 18 (500) On my timing pinion there are 2 cutt outs. I have thought they are there to make it easier to fit a puller. But when I see your pictures, I'm not sure.

I hope you understand what I mean, tried to share a picture but it didn't work. And you must excuse my English, I live in Sweden
Mvh Ybbe