input / output gearbox shaft leak

[Paul MM]

Help!

Having shipped my '55 AJS 350 16 MS from Oz to France to do the distinguished gentlemen's ride later this month i managed to get the bike going after 3 years in a container and was just congratulating myself when there was a 'crack' and the gearbox proceeded to pump its oil out of the input / output shaft onto the floor. gears and clutch all work fine but obviously something is not right. I've spent a day wrestling the gearbox out of the frame ( who the **** designed this thing )and now have a gearbox on my bench. I've always avoided gearboxes ( exploding springs , cogs etc ) but I'm going to have to bite the bullet this time................ Specifically then

- how do i identify which box i have fitted
- does anyone have any immediate idea as to what the problem ( and the fix ) might be
- an overhaul kit might be the answer through the spares dept but tutorials would help - any links?

thanks in anticipation,

Paul

[Duncan]

Hi Paul, if its correct for year you will have a Burman GB/B52 gearbox, if so you will have a circular gear indicating disc just behind the gear lever, some pictures would help confirm. I have not heard of a failure like this before so cant really point you in the right direction of what to look for. The burman and AMC gear boxes are some of the least malevolent to work on so no need worry about working on it. If you dive into the Archive ( http://archives.jampot.dk/technical/Tra ... on/Burman/ ) you will find information on the gearbox.

[Groily]

Welcome to the Club!

https://www.m5poo.co.uk/burman-b52-gearbox/ - This might be of some use.
There's a handy You Tube on sorting the CP box, but the gearchange end is quite different if that's the area of your problem and if yours is the B52 it ought to be for the year.
Can't see a movie on the GB, but maybe haven't dug far enough!

As Spriddler says, doesn't sound like a common issue, and the 'crack' suggests something might have broken I suppose - but do hope not.
Most if not all things can be looked at with the 'box in the frame in fact - but if you've extracted it, makes it easier (until you want to put it back again anyway!) And if there's a damaged casting, just as well to have it all on the bench probably.
Fingers crossed it's nothing too horrendous.

[Paul MM]

Thanks for the initial help, photos of the box below ( GB 28F 55 / 929 / L818 ) which will hopefully help with its identification i have concerns about the mechanics on this as the engine number is 56/G3LS31090. I am surprised that such a massive leak can develope instantly whilst the gearbox otherwise seems to function.

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[Groily]

So when you put oil in on the bench, where does it come out?

Ref the 'clack',did it happen with the engine running, or turning it over on the kickstart, disengaging the clutch, or maybe putting it into gear?

There are a few reasons for 'clacks' of varying intensity, and a few for oil leaks - it's trying to figure if it's 'cause and effect' or 'pure coincidence' that they happened together.

[Ralph]

After 3 years it could be a bad case of wet sumping.

[Paul MM]

Thanks for the feedback, the engine was running with no input from me at the point when the noise and leak occurred. I started it again a day later and the leak restarted after a couple of minutes running without a mechanical noise. I did however check that I could get all 4 gears and that the clutch worked ok. I haven't had the chance to see if oil will drain from the suspected leak area on the bench yet though it appeared that oil had leaked from the imput / output shafts.
Wet - dumping, i' m not familiar with that problem, can you explain further please?

[Groily]

It does sound as if the oil problem could have been wet-sumping then as Ralph suggested - excess oil in crankcase which drips down over time past the oil pump and then is forced out of the breather when the engine is started if not drained first. Breather is close to the gearbox on the back of the motor behind the primary chain case. Can make an alarming mess, but isn't a sign of disaster.

Lots of threads about it on here as it's such a common thing- and discussion of preventative use of taps in the feed line from the oil tank.

If it was that, it should stop after a short time as the oil in the crankcase is sent back to the oil tank. Which might overflow if filled 'full' before the engine was started. It won't leak with the engine stopped.
If it keeps pouring out with the engine running for longer, then you need to check visually that the oil return is working, in case there's a problem there and oil is being delivered and filling up the engine but not being scavenged.

Dunno about the clack. If it was a one off, could just have been the clutch plates separating after being stuck together a long time, or if it's a clack that occurs every time you disengage the clutch, a possible adjustment problem with the 'two plates and three balls' device the gearbox end of the cable attaches to.

Hope it IS just wet sumping. But if it is, you've gone to a lot of unnecessary work unfortunately.

If you stick the required pint or so of oil in the 'box and see if it stays there on the bench you'll have more of a clue. There's a seal and so on to prevent it exiting from the mainshaft sleeve-gear end. If it's only filled to the correct level - using the level plug just behind the kickstart shaft on the casing to see when it's full - then it would be unusual for oil to 'pour' out with the engine running even if the seal was tired. If a blanking or 'core' plug has come adrift, it would be different - but you'll see what's what. When you put oil in.

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On another topic, are you going to register the beast in France if it isn't already? If so, you'll probably want to register it as a Véhicule de Collection', for which you'll need to go through the stages shown here to get an 'attestation' showing it can be granted a carte grise /certificat d'immatriculation, and you might need a 'quittance fiscale' if it's come from Oz. https://www.ffve.org/attestation-ffve-p ... collection is the place to start creating the necessary dossier if it's the way you're intending to go.

[Duncan]

If you don't need to dive further into the gearbox it would be a good idea while you have access to replace the oil seal over the sleeve gear and the spacer it runs on if it has a wear ridge on it.

[Paul MM]

Good afternoon everyone - thanks for the help and advice. I'm currently at work and can't chase up all the suggestions at the moment. I can be 100% certain it's not wet sumping - had that previously. I'll see if i can persuade the gearbox to 'leak' from the suspected area on the bench. The gearbox level hasn't been touched of late and hasn't leaked before so it is unlikely to be overfilled. The oil definitely appears to be 'pumped' as it takes a minute or two for the leak to develope with the bike in neutral so it must involve the spinning input shaft and anything associated with that. I'll know more after the weekend.