Laydown gearbox leak

Peter, talk to Mike Pemberton, singles specialist. I don't think there is a seal there, at least not a proper one, maybe because it's above the oil level? Anyway, that's why it leaks. When Mr P rebuilt my gearbox he did an oil seal mod, now no leaks from there. It leaks freely from the kickstart shaft though. Be sure you aren't overfilling the gearbox, you'll cause an environmental incident if you do.

Adam

Rob, originally there was only an oil slinger fitted up against the open bearing, which slung some of the oil away from the bearing when the bike wasbeing driven. Once the bike was stopped andwas layed over on the side stand the oil simply ran behind the slingerand outbehind the sprocket.

If you fit a #1654 2rs bearing (2rs = 2 rubber seals) this will easily keep the oil in. No need to have any alterations done to accomodate a separateseal. Iflicked out the inner most lipseal on the bearingto ensure the oil would be constantly washingit and found that onlythe outer most seal is adequate to retain the oil. This leaves the box oil to leak out, as mentioned, from the kicker shaft. Though, 'O' rings can be fitted on the shaft (after a slight mod)to slow this leak.

Paul.

Has anyone tried using semi liquid grease in a laydown box? I've used it in burman boxes successfully and was going to try it in my inter gearbox even though I put a sealed bearing in it.

thanks

Mark

I have just topped my Laydown box up with oil and it is pouring out past the main bearing. I fitted a sealed bearing as this thread suggests just over a year ago and I'm sure it never used to leak like it is now. I am worried about the amount that is coming out as i don't wan't to run the gearbox too low on oil and cause damage. It already whines a bit in 3rd gear.

I'll take it appart at some point and try and find you source of the whining and could fit an oil seal then, but has anyone had this problem persist after replacing the bearing?

I'm using straight 50 engine oil in the box, what do other people use?

i put half a pint of oil in mine as i think it recommends any more than that it just pours out when on the side stand . and on a run it gets sprayed everywhere even on the rear tyre not good .Baz

Hello,

This has not much to do with the laydown gearbox unless it can be fitted (with a slight mod) to the kickstart shaft.

On AMC gearboxes, oil soon leaks out of the kickstart shaft when an "O" ring is fitted and bad leaks end up with burnt oil on the exhaust pipe/silencer. Try fitting a quad ring (or a "X" sealing ring as it is known in the AJS/Matchless OC) instead which is a straight swop.

I have just replaced one after ten years without a leak until last year and even then it was only a small leak. They are obtainable from Norvil at 29p plus postage/VAT, part Number 069595 (replaces 040005) - page 21 of 2015 parts list. Try ordering with other parts as the postage/packing will be excessive compared to the cost of the quad ring.

I believe that the Commando gearboxes have a proper spring backed seal fitted at this position and this mod can be incorporated on earlier Dommie/Single AMC boxes but it comes with a more substantial cost.

Regards,