A10 Oil leak into primary Cain case (belt drive)

[rwbeard]

Hi there,

Some of you must recognise the feeling, it just knaws away at you, until you give in... So a couple of months ago I purchased a number of months ago a RGS Replica. A 1957 frame, 1962 RR engine - and looks new, because it virtually is. The engine was rebuilt by SRM at a cost well in excess of £5K, this was in late 2007. The bike has only just been finished and put on the road in 2013 by myself. It has a belt drive primary drive and clutch fitted and a RRT2 gearbox.

The problem. I had been out on two short "shake down" runs, and she's sweet. My first old brit twin (not sure that clip ons at my age is a good idea...). The last run was a bit longer, about 15 miles, briefly topping out at 60 mph, but staying between 40 & 50 mph for most of it.

Returning home, a small pool of oil from the primary drive side, and smoke from the belt drive clutch - burning oil.

I took of the primary drive cover & had about 50ml of oil inside the case.

So some questions to those who either have experience or advice

1. Any ideas as to where the leak has come from (I presume it's from the engine?)

2. Why is it leaking

3. An effective cure - what to do next

I have posted photos.

Many thanks in anticipation

Regards

Bob Beard

[muskrat]

G'day rwbeard, welcome to the forum.
The only place it could be from is the engine. Crank seal is the obvious. It seals on a cush drive distance piece on the crank. Sitting for 6 years the seal might have hardened or the cdd has marks/rust/worn.
Cheers

[bsa-bill]

Could engine breathing (pressure) be involved I'm thinking new rings, blow by

[cus]

There may have been an excess of oil in the sump, forcing it out round the seal or cover bolts on that first run, after sitting around, maybe clean it all up
empty the sump & take it for a good spin, if it still comes out, plan B,

regards, Cus

[RichardL]

Bob, Welcome to the forum. Very nice bike you have there. Was oil flying out out of the viewport? It looks red, and many of us use ATF for our wet clutches. It's not ATF, right? So, it must be seal, as Musky (mentor to manY) says.

Richard L.

[rwbeard]

Thanks for all of your comments, most helpful


If it's the drive side main bearing oil seal, can this be replaced without taking engine out and dismantling?

If so, any tips for removing drive pulley locknut, looks like liberal use of locktite involved at some time.

I don't think it's oil from gearbox, but there's no primary case oil used in this case. I might just run the engine for a while & watch where the oil comes from.

Regards

Bob Beard

[bsa-bill]

Seal can be replaced after removing the primary case, no need to split the engine.
Loctite responds to heat, a heat gun is good and safer than a torch.

apart from the seal there are those two studs (behind the crank) that hold the primary on as well as the tree long front primary screws

talc fluffed about has been suggested many times here as an indicator of liberated oil

[morris]

If so, any tips for removing drive pulley locknut, looks like liberal use of locktite involved at some time.

As Bill suggested, heat will help. Some parts suppliers sell a special tool for this purpose. I recently bought one, but I find it a bit flimsy.
Sometimes only brute force will help. I got it off by knocking with a hammer and a bar of soft aluminium from about 1 1/2 X 8 in.

[rwbeard]

Thanks again for your help, I really like the talc idea for finding oil leak sources!

Before I get to work....

Any tips for locking up the engine in order to remove the drive nuts off the primary drive pulleys?

I will let you know how I get on.

Regards

Bob Beard

[KiwiGF]

Oil comes out of the front primary bolt holes if you run the bike without the outer primary cover on, you may need to block them with shorter bolts and washers etc......found this out by gettting oil on my left boot after riding a few miles to make sure the clutch was good before the outer cover on......make sure any temp bolts fitted to do this do not foul the crank !

[RichardL]

Bob,

I've done the tightening and loosening of my cush nut (you have a different nut) by putting the bike in gear while on the center stand and stomping on the break pedal while operating a long breaker bar or torque wrench (depending on whether it's being loosened or tightened). A bit of a balancing and controtion act. I found that I had to overtighten the clutch springs during this operation to avoid slip, then, readjust the clutch when done. I will patiently wait for our friends here to tell me that I should not have needed to tighten the speings if the clutch was adjusted right in the first place. Maybe, but that's not how it proved-out for me.

Richard L.

[muskrat]

 I use a rattle gun (air impact wrench) without having to lock up anything. I have similar primary.
Cheers

[Greybeard]

I use a rattle gun (air impact wrench) without having to lock up anything. I have similar primary.
Cheers

Great looking machine there!

[bsa-bill]

used Richards method all my bike life, but never again, new rear brake cable snapped and I went A*** over T** to the floor banging and stretching muscles and bone on the way, took a good six months for all the effects to disappear.
Please buy yourself a clutch locking tool Richard, it's a little more work but well worth it.

Agree with Musky - a rattle gun is good

[RichardL]

used Richards method all my bike life, but never again, new rear brake cable snapped and I went A*** over T** to the floor banging and stretching muscles and bone on the way, took a good six months for all the effects to disappear.
Please buy yourself a clutch locking tool Richard, it's a little more work but well worth it.

Ah, yes. I remember your story. Glad your better. So, where does one buy a "clutch locking tool"? Seems a good idea, even if it also seems unlikely I will snap my brake rod.

Richard L.