Clutch oil seal and sleeve gear bush

[Blackthou]

In reality, things should only leak for a reason.

One is wear generating more clearance, another is faces that aren't flat either due to distortion, burrs or debris.

Incorrect assembly is another, bad gasket, poor jointing if required. Faces should be lapped flat and or stoned. Careful prep is essential.

I've found small weeps after a decent run and on one occasion it was down to slightly too much oil which when thinned with heat and aerated sneaked out of the oil seal. I bought a new seal to eliminate it but eventually found - by using the level plug, it was a touch overfilled.

There are others but with care can be identified and eliminated but only if it bothers you. The main thing is to enjoy your ride or tinkering if you can't.

[Phil C]

Hello everyone. Here is an update.(now come on, there's no need to groan.) Went for a ride this morning with an emptied pc.  Just a couple of miles.  The photo was taken when I got home. No dribble apparent, but a bit of oil on the bottom of the pc. So, I'm thinking the leak is probably coming from the pc. Obviously, nagging uncertainty remains, esp given that some experts on this forum have fancied it might be coming from the gearbox. Anyway, I think I'll have another look under the clutch.
I've made a little list of what I should buy:
- pc gasket
- circular cover plate gasket
- clutch oil seal
- gearbox sprocket oil seal??
- felt washer
- alternator rotor tab washer
- clutch tab washer
- alternator wires grommets
- chaincase plug screw with baffled breather
Is this right? Have I missed anything?  All comments much appreciated as always. I always find them very useful and very interesting.         Phil

[Phil C]

Just put 1/4 pint of oil in the pc, and went for a ride - same distance. When I got home, had a look:  a slight leak, but not much atall. In a way I'd have preferred more, as it would have helped the diagnosis.  I still think it's from the pc, but  also that having had too much oil in the pac at one point might have made it significantly worse at that time.  So anyway, as I said on my previous post, I'll take the clutch etc off and have a look.  But I guess it's not urgent, esp as the leak is not exactly rampant.    Phil.

[Blackthou]

No groans from me Phil. I enjoy following your posts especially as you're enthusiastic and keen to learn plus I often learn something from the advice from others.

Before you embark on your project, it could well have been too much oil initially and you were encountering the consequences. I know you've added 1/4 pint but that aside, did you use the level screwa and let it bleed from there? IMO it's a better way to sort your level than dispensing a set amount.

If you have too much oil you will probably see what you did before and strip the clutch when it wasn't the culprit.

Your list looked pretty comprehensive but if your bush has a split in it or is loose on its shaft it will leak and counter all your stirling work. If the bush is plain on the diameter and there is a groove worn by the oil seal, unless its symetrical, reverse end for end so it tracks on a different position.

As always, good luck

 

[Phil C]

The bike has been stood unused for 2-3 days, on its sidestand. Out of interest, I had a peep underneath just now. The wall on which we've seen the dribbles was pretty much dry. If the leak there was from the pc, then I guess that's what we'd expect.

But also visible - see photo - is a drip of oil with what I think is the colour of the dye I added to the gearbox.  The drip tray underneath is pretty much dry. If there have been any drips into then they've spread out and are now just part of the general oily film coating the bottom of the tray.  So it looks like, literally, a drip or two over a couple of days from a stationary gearbox. So not too bad. But I guess there might be more if the gearbox were running (moving parts, warmer so thinner oil.)

Could you tell me please: where the drip of orangey-coloured oil is showing, whereabouts on the gearbox would you say that is coming from? It's hard to tell where the drip is coming from because, running my finger around the surfaces, they feel dry.

Phil.

[Greenfield]

You should just be able to see the layshaft bush as a bronze disc between the mainshaft (connected to the gearbox sprocket) and the bottom of the gearbox. This sits below the oil level tube and if its not a good seal with the casing, you'll get the odd dribble here, particularly after a run. Its easy to replace or seal, but unfortunately you can only get at it from inside the gearbox.
Have a really good look underneath to the right of the lower chain under the sprocket. If there's oil between the sprocket and layshaft bush, the problem lies with the mainshaft oilseal.

[Greenfield]

Hi Phil
Additional to my last post, check whether the hole in the gearbox filler cap is clear to stop any pressure build up in the gearbox.

[Phil C]

Just had a roll round on the garage floor, can't see a bronze bush, but the bike's on its sidestand which I imagine might make it impossible to see. I'll heave it onto its centre stand tomorrow and have another look.

[Phil C]

Hi Phil
Additional to my last post, check whether the hole in the gearbox filler cap is clear to stop any pressure build up in the gearbox.

Yes the hole is clear, thanks.

[Greenfield]

Hi Phil
Pic 1 taken through the sprocket window behind the clutch, shows the layshaft bush just below the bottom teeth of the gearbox sprocket. Its a bit dark I'm afraid.
Pic 2 is taken with the gearbox empty, the bush is central and the oil level tube is at about 5 o clock.

[Phil C]

You should just be able to see the layshaft bush as a bronze disc between the mainshaft (connected to the gearbox sprocket) and the bottom of the gearbox. This sits below the oil level tube and if its not a good seal with the casing, you'll get the odd dribble here, particularly after a run. Its easy to replace or seal, but unfortunately you can only get at it from inside the gearbox.
Have a really good look underneath to the right of the lower chain under the sprocket. If there's oil between the sprocket and layshaft bush, the problem lies with the mainshaft oilseal.

Thanks for this. I guess I can only see the bronze layshaft bush when I've got the clutch off?   Phil

[Greenfield]

From the right side of the bike if you feel around the back of the gearbox where there's a rounded bump on the bottom (this houses the layshaft gears), when your finger tips touch the chain coming round the bottom of the gearbox sprocket, the flats of your finger tips will be against the layshaft bush.
Sounds a bit complicated but should be straightforward. For a better view, the bike needs to lean to the right, ie not on the propstand, and look from the primary side.

[AWJDThumper]

Sorry to correct you, but what you feel on the outside is a cap that seals the hole in which the layshaft bush fits - you can't feel the bush itself. In principle, it could leak oil but this is only likely if someone has inadvertently disturbed the cap at some point - for example, while trying to get the old bush out.

[Phil C]

I've been struggling to put arrows on my photo. 

Placing my camera where I can't get my head, I think I now have a photo of it. I think the cast boss (top arrow, if I've managed to put an arrow there) is where the cap and bush will be, though they aren't visible from this angle?

I'm not sure what the other bit (bottom arrow, with any luck) is.

Phil.

[Greenfield]

Sorry to hijack your post Phil but I've just taken another photo of the layshaft bush/cap through the gearbox sprocket cover. What I take to be the bronze bush is centre photo below and behind the chain. AWJDThumper is saying that this is a cap. I can't see evidence of a hammer and screwdriver botch and I'm pretty sure that this is the back of the bush. Can someone clarify this?