G/S oil leak - any 2nd opinions welcome!

bakerlonglegs

bakerlonglegs

Relative numpty
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The bike's been dripping oil from the back of the engine/oil pan. Started with a couple of drops after a Sunday ride, but now getting worse. :(

Looking under the engine, the little shelf over the oil pan under the rear engine mount is wet with oil and there's drips from the bottom edge of the gearbox casing under the flywheel, right round to the slot where the clutch cable sits. The back of the oil pan is slick with the black stuff, above the line of the oil pan seal (which rules THAT out).

Sooooooo, my guess is there's a problem with the oil seal between the crankcase and the flywheel. First thoughts are I need to remove the gearbox to investigate further, but if I'm right could it be engine out (again :spitfire) to fix?

Any thoughts/opinions/abuse gratefully received!

:beerjug:
 
Think you're right I'm afraid, sounds like rear oil seal. Post ride leak presumably as oil is thinner as hotter.

How about a tech day? I keep reading about these in the US on the R90S forum. A bunch of airhead tossers could come along for the day, generally provide advice and abuse whilst watching you scrape your knuckles and drink you out of tea and coffee?
 
The joys of airhead ownership?

The good news is if the rear seal has gone you can do it in situ.

Is it definitely engine oil? it could be the gearbox seal. I can't remember if you had your gearbox rebuilt. The seal on the input shaft will eventually cut into the input shaft bearing sleeve allowing it to leak. Before you check any of that make sure the gearbox breather hole is clear, if it's not the gearbox will leak out of it's weakest seal when it warms up.

If it is the engine seal be very careful when you remove the flywheel, the crank can move forward and drop. It's best to remove the front cover and wedge a piece of wood between the alternator rotor and the cover.
 
Will said:
How about a tech day?
Click to expand...

We had a couple of those a few years ago. Kev (Waldin) has had his drive block paved since though and has banned airheads after mine leaked oil on his new blocks :D We'd have to find a new venue for the Midlands.

Good idea Will are you volunteering? :thumb2
 
^^^^^^^^^^^^^^^^^
What 'e said :)
If it's the back oil seal. it's not to bad a job to do:thumb2
Front g/box oil seal can be more troublesome:(
but it is do-able by a relative numpty :augie
Post pics when you got g/box out...


ONE other thing, make sure it's not the engine breather under starter motor leeching down the casings and collecting on top of sump ledge...

Now THAT is a piece of piss to cure :thumb2
 
Rob Farmer said:
We had a couple of those a few years ago. Kev (Waldin) has had his drive block paved since though and has banned airheads after mine leaked oil on his new blocks :D We'd have to find a new venue for the Midlands.

Good idea Will are you volunteering? :thumb2
Click to expand...

Bugger I'm too far away, but I have a barn available, with 2 bike lifts, one a ramp type t'other side lift and it's covered [waterproof]:)
Maybe sort one down yer'e in DEVON I can also arrange a camping field, plus if required, A Turd Tardis..:D

I've also got a "few" airheads you could dismantle and practise on :rob:rob
R80/7 R60/6 R26 etc etc
BUT NOBODY touches me 90s cept me :D
Maybe discuss it at Baskerville :thumb2
 
bakerlonglegs said:
The bike's been dripping oil from the back of the engine/oil pan. Started with a couple of drops after a Sunday ride, but now getting worse. :(

Looking under the engine, the little shelf over the oil pan under the rear engine mount is wet with oil and there's drips from the bottom edge of the gearbox casing under the flywheel, right round to the slot where the clutch cable sits. The back of the oil pan is slick with the black stuff, above the line of the oil pan seal (which rules THAT out).

Sooooooo, my guess is there's a problem with the oil seal between the crankcase and the flywheel. First thoughts are I need to remove the gearbox to investigate further, but if I'm right could it be engine out (again :spitfire) to fix?

Any thoughts/opinions/abuse gratefully received!

:beerjug:
Click to expand...

I have the same leakage on my G/S but haven't had time to fix it :(

Besides the mentioned oil seal, is there a chance that it might "just" be the o-ring for the oil pump cover?

Cheers,

Dan
 
Thanks for all the wise words, and rapid too :bow

nud1e said:
rear crankshaft oil seal. You can change it with the engine in the frame, by removing the gearbox. Overfilling the engine with oil is one possible cause.
Click to expand...

Rob Farmer said:
The joys of airhead ownership?

The good news is if the rear seal has gone you can do it in situ.

Is it definitely engine oil? it could be the gearbox seal. I can't remember if you had your gearbox rebuilt. The seal on the input shaft will eventually cut into the input shaft bearing sleeve allowing it to leak. Before you check any of that make sure the gearbox breather hole is clear, if it's not the gearbox will leak out of it's weakest seal when it warms up.

If it is the engine seal be very careful when you remove the flywheel, the crank can move forward and drop. It's best to remove the front cover and wedge a piece of wood between the alternator rotor and the cover.
Click to expand...

Joy indeed! I was out for lovely run today, thinking what a damn fine bike this is..... Ne'er mind, it'll be back out again, soon as poss. :D

If it is the rear engine oil seal, good to hear it can be done in situ.

Cheers for the lateral thinking on the gearbox, I hadn't thought of that :blast , will check it out.

Proff said:
but it is do-able by a relative numpty :augie

ONE other thing, make sure it's not the engine breather under starter motor leeching down the casings and collecting on top of sump ledge...

Now THAT is a piece of piss to cure :thumb2
Click to expand...

That's me! I think I'll add 'relative numpty' to my sig.... :o

I'll check the engine breather, thanks for the tip off :thumb2

Keen to get this sorted, had plans to take the G/S to Baskerville..... :(
 
Proff said:
Bugger I'm too far away, but I have a barn available, with 2 bike lifts, one a ramp type t'other side lift and it's covered [waterproof]:)
Maybe sort one down yer'e in DEVON I can also arrange a camping field, plus if required, A Turd Tardis..:D
Click to expand...


Good idea Proff? Airhead only weekend. Throw a few spanners about, get drunk and crash out in the camping field :beerjug:
 
be very careful. :eek:

When replacing the rear crank seal, put a thin block of wood inbetween the front cover and the alternator.
It's very easy to have the crank thrust bearing "pop" of it's spigots, as the crank moves when removing the flywheel ( which entails an engine apart job to get it back in place).

By having something under the front cover against the alternator it stops the crank moving. :thumb
 
Steptoe said:
be very careful. :eek:

When replacing the rear crank seal, put a thin block of wood inbetween the front cover and the alternator.
It's very easy to have the crank thrust bearing "pop" of it's spigots, as the crank moves when removing the flywheel ( which entails an engine apart job to get it back in place).

By having something under the front cover against the alternator it stops the crank moving. :thumb
Click to expand...

Will do - thanks for the tip-off :thumb2

First steps will be to check the various breathers and then get the gearbox off for a look-see - pictures to follow.

Thanks again for the advice, one and all :bow
 
leak

Make sure its not the oil pressure sensor before you start ripping the gearbox out.
I was going to do that but then the sensor leak got worse and it became apparent what the problem was. They fail and leak thru the plastic centre bit
 
Well, after an evening with the spanners out, I've established:
- it's not the oil pressure sensor leaking
- it's not the engine breather, either blocked (valve is OK), kinked or leaking down behind the airbox
- it's not the gearbox breather (hole clear on speedo drive bolt)

I've given the whole area a good clean to get the now-dusty oil plus road muck off. Will take it for a spin tomorrow and see if I can pin down where it's coming from and hopefully whether it's gearbox or engine oil.

We continue.
 
Park it over blotting paper, the molecular sieve will separate the constituents marking it as engine oil or gearbox oil with comparison.....
 
alimey4u2 said:
Park it over blotting paper, the molecular sieve will separate the constituents marking it as engine oil or gearbox oil with comparison.....
Click to expand...

That's a good suggestion, cheers :thumb2

Drips dripped, together with some fresh gearbox and engine oil for comparison, and some from the dipstick....
 
Just to draw a line under this little tale....

Got my bike back from Scrimingers yesterday (top bloke, as reported by Rob elsewhere). Turns out the oil was engine oil, weeping from one of the oil pump fixings that had been drilled too far and gone through into the crankcase. Not much of a leak, but enough to drip when the bike was warm and running. Now sorted. :thumb2

While it was there, also had the charging problems fixed (duff alternator plus poor earth to frame) and a minor leak from the final drive fixed (OK, for the record, the books didn't mention a gasket when I rebuilt it.... :o ), plus a couple of other bits and pieces and a tune-up.

Now running schweeeeet! 80-85mph run all the way home..... OK summer, NOW you can arrive.... :cool:
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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