B44SS oil leak

[Flat Tyre]

Bike has developed a persistent leak from around drive sprocket, so have stripped it down so far to the drive sprocket nut as I intend to change the oil seal behind it.Engine is still in frame, what's the best way to loosen/ tighten sprocket nut?
I have a deep socket to fit coming via snail mail, and have plenty brute strength and ignorance at hand. What's best way to lock sprocket.
Thanks in anticipation

[rhyatt]

knock back the locktab - put it in gear and put rear brake on hard - undo the sprocket nut.

dont forget to replace the felt dirt seal between the plate behind the clutch and the sprocket ( keeps muck off the pushrod) and also check the state of the protruding high gear bronze bush sticking out of the high gear ( this engages with the plate's oil seal) my oil seal had munched a slot in the bush

[Flat Tyre]

Thanks for the info rhyatt, I have the felt washer replacement but didn't realise the oil seal on the plate ran on a bronze bush. It looks ok but difficult to determine any wear. Guess this would be a gearbox strip to press it off

[cdsdorset]

Use silicon sealer on the splines.

[rhyatt]

https://www.ebay.co.uk/itm/354853520878

this bit of the bush sticking out of the gear is the bit that runs in the oil seal placed in the inner primary chaincase back plate - keeping oil in this primary chaincase.
over time the oil seal spring pressure can munch a groove in this protruding bush.
yes - gearbox strip

[Jim S]

Hello Flat T

Last year I had replaced the gearbox seal and the sprocket on my B50 and I still have a gearbox oil leak in that area. I think it is a stretch to expect an oil seal to function in that environment.

Some experts at the B50.org Forum recommend installing a sealed bearing at the output gearshaft location. Positive long term results have been reported in that forum with a sealed bearing.

Jim

[Flat Tyre]

Hi All
OK, I have now replaced the seal on the gearbox high shaft, interestingly the bearing behind that is sealed. I measured the bush that the small seal on the plate behind the clutch runs on, and it fine. Replaced said seal and the gasket. Replaced primary gasket, boxed all up and filled to correct level with oil.
Started up and horror, still got some oil appearing on the bottom of the primary chaincase and dripping.
Question, is it possible main seal on crank could be leaking, blowing oil/pressure into primary?

[DAVE BRADY]

Hi,

Oil can end up dripping away from where it is getting out.  Try completely cleaning all the under side and rear of the case. Run the engine and use a mirror to get a better view.
Also, if the crank seal has gone there would possibly be a bit of blowing out of the primary when the cap is removed.

Dave.

[cdsdorset]

Get some oil dye and a uv light and find what you are actually dealing with.

[rhyatt]

It can also come out of the grommet where the alternator wires come through

[Flat Tyre]

Thanks all for the reply's.
I've stripped down the primary again, to check the seals I replaced. A couple of questions -
Something I didn't notice before on the high gear bush the small seal runs on, this bush seems to be a split bush, is that a modification, or would it let oil seep out?
I want to replace the main crank seal on primary side, what best way to remove the thrust plate that sit in front of it.
Appreciate your help!

[rhyatt]

From memory , that thrust washer is there(in different thicknesses) to align the sprocket and clutch basket sprocket.
It can come straight out , noting the chamfer , try a couple of strong magnets , then tease out the seal.

[limeyrob]

Is the oil leaking down the rear of the primary chaincase (in front of the final drive sprocket) or the gearbox (behind the sprocket)?  If its chaincase oil its the seal on the bush and if its gearbox oil is the seal running on the sleeve gear.  The leaked oil should look  different.  Is the gearbox oil going down?
If its chain case oil is this getting too full from oil blowing past the crank seal?