Haemorrhaging oil from transmission side - possible causes?

[RDfella]

50 ft/lb and some loctite for the A10 clutch nut.

You sure that's for the semi-unit? Those split collars don't have much to locate on.


PS - agree with SHM - that shock absorber somehow doesn't look right.

[Swarfcut]

  RD's right. The split collar hangs on by its fingernails, that one has no chance with that much wear on the shaft. The shaft, split collar and thrust washer need to be in good order, the ensemble positions the clutch chainwheel in relation to the crank. Thrust washers came in different thicknesses, and along with shims between the crank drive sleeve and main bearing inner race the chain alignment can be made spot on.
  Looks like a combination of worn parts and a bit of a bodger's idea of assembly. From experience factory rivets are head to the clutch, those look likes someone else with a poor grasp of the metallic arts has been there. My guess is the seal ain't even the right one. You'd get a better seal by cleaning off the oil, greasing the shaft and filling the gap with bathroom silicone as a temporary measure. Changing the seal is an engine out job, but the mainshaft can be changed without disturbing the gearbox casing, but with a fair bit of under the bike grovelling.
 Pictures of the cush parts would help get a handle on this, I know the hassle of the big nut, but witness marks from the chain are something that needs a good looky.
Plunger  Cush Drive is two lobe type, tips of the sliding member pass within the sprocket centre. Unlike the S/A type, the lobes do not mesh closely as pictured by mitch. That's why it looks a little different.

 Swarfy

 Additional  B Series drive sleeve won't fit an A series crank.....the splines are different. So care needed if you're buying on ebay

[owain]

Here's a few pics of the cush drive and the damage to the transmission casing.

The first picture shows the amount of wear between the worn parts (on the right of the image) and the parts I replaced these with (on the left of the image).

The second and third pictures show the dismantled cush drive.

The fourth picture shows the wear behind the cush drive. Bear in mind that the inner heavily scored, circular pattern is from the worn cush drive. The semi-circular scoring above this wear could be new however.

Thanks for the tips on the mainshaft. It's a nasty hit to the wallet but could well be worth it as I do use my A10 regularly. Although what about just simply tack welding the collets to the mainshaft and filing down any weld protrusions ...or would this relegate me to the realms of  the botched-job mechanic? 
 

[berger]

is this a plungy mainshaft 10/1/2 inch long , i don't need it if it is or even if it isn't   googled it and it is a plungy mainshft

[muskrat]

G'day owain.
Definitely something fishy going on there.
Firstly that chain is knackered and should be an endless chain, I'd never use a primary chain with a split link.
Secondly your motor has the oil slinger and it looks like you replaced the sleeve with the later "oil seal" type. I recently converted my plunger to the later type.
The old sleeve and sprocket looks to have been modified. Also something doesn't look right with the slinger, is it loose?
Sorry have to go to work so I'll be back in 10 hours.
Cheers

[owain]

Thanks all, this seems to be getting more expensive to remedy by the minute  . Sent you a pm @Berger.

I see what you mean SHM, the lobes are very different in Mintos pics.

I'm abit confused re the oil slinger and sleeve though Muskrat. Do you mean that protruding piece of metal that is poorly riveted onto the casing behind the clutch?

It does look like the cush drive assembly needs replacing. I had no idea that there was an oil seal type sleeve though. Haha and all this started with just wanting to replace a clutch oil seal

[Minto]

The oil slinger is the funny shim thing with the odd shaped holes that sits inside the crank case between the crank shaft bearing outer and the splined sleeve that the engine sprocket locates on. You can see it on the last picture of page 2 of this thread.
Regarding your oil leak, have you checked the state of the outer case? My clutch had come loose recently (due to, I think, a knackered clutch nut locking washer). Anyway it had worn through the casting around where the case screws go, and was letting a lot of oil past.
If you haven’t already, take a read through those posts as you seem to be having very similar issues. Chemical metal and a bit of filing has sorted the outer case ok. Still have other leaks but they’ll have to wait til winter.
Oh, and that oil seal behind the clutch looks way knackered!

[Swarfcut]

  Owain..Those new cush parts look reasonable to me. The engine is the earlier non oilseal version and the drive sleeve required is a close fit in the hole, well at least it was when everything was new. For preference a sleeve with a scroll edge has a better chance of keeping the oil in the right place than the plain edge type you have there. In the grand scheme of things this is a minor detail.

 The split collar can be turned over to present a best edge to the mainshaft. With everything assembled correctly and tightened up, good chance it will be a runner, if not time for some planned spending. Welding the collar onto the shaft will mean you can't get the thing apart in the future without major destruction...and will also ruin the seal.

 A brand new expensive mainshaft is out of my league when there is no shortage of good used ones, either on ebay or from reputable sellers, at a cost effective price level.......you could buy a complete gearbox for that sort of money.

 Minto and Devlin are in the same sorta boat, lots there so no need to repeat my thoughts. There should be no end float on the mainshaft. This is controlled by the small mainshaft ball race at the kickstart ratchet end. This bearing is located by a circlip, which if loose or missing will allow the bearing and shaft to move to the timing side and the chainwheel to contact the primary case. Just worth a quick check.

 Swarfy.

[muskrat]

G'day owain.
Starting at your 1st photo in reply #29. The sprocket on the left is good, the sleeve on the right is correct. The reason for the horrible gouged on the crank case is due to the recess in the sprocket on the right causing the sprocket to be too far inbound. This would put extra stress on the clutch and ruin the chain.
If you re-use that chain don't blame me when it goes belly up!
New collets and rollers won't break the bank.
As for the mainshaft seal it looks like it's been fked with before. Unfortunately it's big but not expensive job to fix.
Pics are of the correct sleeve for your motor.
Cheers

[Minto]

Musky, glad you posted that, as that’s the same as the one I’ve just swapped onto mine. There seemed to be a lot of variations of this part. Swarfy posted some pics a while back of three different ones, 46mm plain, 46mm scrolled edge, and 43mm plain for the oil sealed motor,but the one with the recessed section on the face is what I’ve got. Thanks for confirming it’s right, my motors the same age as Owains.

[chaterlea25]

Hi All,
I would have thought that the cush drive sliding surfaces should be a close fit to each other 
I'm not very familiar with the plunger bikes vagaries though
Owain, spend some time getting the sprockets lined up correctly for your new chain
I know that the thrust washer behind the clutch was available in different thicknesses, but you may have to shim at the engine end, shims would need to fit inside the cush drive sleeve

John