AJS & Matchless Owners Club

Just received a new design chaincase seal (thank you AMOC Spares - great service). When fitting, does one need to use wellseal?

No, but you may need a washer or two on the centre stud. Also you usually need to shorten it a bit.
Dave.

And don't forget check the oil regularly. Water will get in the chain case, having sealed it, the water will not seep out. Chains, clutch and bearings will not like rusty oil.

Gents, thanks for the advice. Hmmm, perhaps there's something to be said for a leaky chaincase after all.

You're joking (I hope) there's nothing good about a leaky chaincase. Fit the new seal and fill it until it just touches the very bottom of the primary chain. It won't leak and no water will enter unless you ride very slowly through a very deep ford.
Dave.

I guess you never rode an AJS or Matchless every day back in the 50's / 60's Dave. Plenty of times I had water in the chain case. The only reason you do not get water in the chain case now, is because the bike is in the garage. I had to ride through flooded roads on my way to work. You have less chance of having to ride through a flooded road now. Expect water in your chain case if you do. If you had to ride on the road to work in the picture below, you would need to know where the road is. I think you were a 12 year old when I had to get to work through that water.

Well that's what I said, don't ride it through deep water! The only time I had water in the chaincase was when we were flooded out with 15" of water through the house and shed.
Dave.