PRIMARY CHAINCASE CLUTCH SHAFT SEAL-4 stroke

[Les H]

Hi All. I renewed the chaincase oil yesterday. Filled only to the level hole. I started the engine and oil poured as if from a tap onto the garage floor from what must be the gearbox shaft...I checked the DRAGS site but could not find anywhere that mentioned a seal. However on the video I show (link) it does show a felt one at the rear, which is what I would have expected. Nortons and AMC have the seal in a sliding plate that can accommodate gearbox movement for primary chain tensioning. Is this the same please? I would also like a pointer as to where I can get the seal and any extra bit of info as regards stopping the entire oil volume from being ejected out...Doh! ...The seal is shown near the end of the video: https://www.youtube.com/watch?v=RHrplqoO0z0&t=270s

[Les H]

I've just found that DRAGS say NO SEAL was ever fitted So if no seal exists there can be no wear on the sealing method from what was there at manufacture...Right? I cannot believe the bike (a VH) would have been produced so that the correct amount of oil would just spew out in seconds!...What's wrong chaps?...Before I start, it's nice having some background on the problem...Many thanks

[Mick D]

Hi Les

I don't own a VH but I always top up the PCCs on all of my classic bikes so that the oil just touches the lowest part of the chain run, any more is just asking for it to be thrown out

Regards Mick

[dave.owen]

I lean my vh over at 45 degrees , on the nearside.wen oil cones out of the level plug its about right.

[Roger Gwynn]

There must be something fundamentally wrong with your machine to leak oil like that. Have you had oil in it before? There is no seal fitted as standard although some owners do fit things. The oil is prevented from leaking by being thrown outwards off the clutch and from dribbling through the mainshaft hole by the lip on the inner chaincase that is either cast in or a sheet steel pressing, depending on year. The lip is very close to the rear of the clutch and is sometimes damaged or missing. It is chaincase oil and not gearbox oil? Filled to the 3/8 level plug near the bottom of the case not the big 1-5/8 filler plug at the top, which has been done? I couldn't see a felt seal in the video but did spot several other errors with the bike!

A model and year is always useful to know when trying to diagnose problems.

[Les H]

Thanks very much Mick, Dave and Roger. The idea of putting just enough oil in it could work as there was SOME oil in it and it didn't leak, well maybe only a little. I had the bike on the stand and level and filled a touch too much and let the small screw level hole drain it off. I used just some multigrade engine oil I had around. The 45 deg leaning trick would probably reduce the amount to about half and still lube the chain so a good idea Dave. Thanks Roger for pointing out what I should see on the inner chainguard when I take off the clutch to examine it. That might be in a few weeks time as all I want to to do now is ride it to try it out after buying it and putting right the obvious things to sort out the basics. My bike is a 57-59 one....yes it has bits from a 57 and 59 unfortunately ...Then again it would not be the only one like that I suppose? I understand the centrifugal principal of flinging the oil away from the shaft but the oil seemed to pour oil when ticking over...maybe the deep oil was carried round in big quantities and fell onto the centre as it passed over the clutch top. The geared down clutch, at slow tick-over speed, turns too slowly to fling off the oil? Anyway, thanks again, will take some photos and report back here as soon as job attempted. Hopefully I'll find that "lip" on the chaincase. For now, I'll remove some oil and have a ride on it...Cheers

[will_curry]

Another source of unexpected oil on bikes fitted with the fully enclosed chaincase
is the chain oiler from the oil tank. It should have a small felt plug in the pickup in
the top of the oil tank. I've known zealous owners remove the plug which regulates
the flow of oil from the tank . . .

I've also fitted a gearbox without checking properly that the core plugs were all
present and correct. As soon as I started the engine the gearbox oil poured out.
What fun I had stripping all the primary drive off again.

[Les H]

Thanks Will. Yes I did notice that some oil was dripping out of the full rear chain guard. I looked into the oil tank after removing the cap but all I could see was a spring that held down the oil filter which is weird and unlike the filter on my VB. The VH one is over six inches long and thinner. The mesh is very fine (or blocked) as when I pull it out it hardly drips oil. Apart from that there does not seem to be any other pipe outlet out of the tank to feed a chaincase oiler. I've seen it mentioned in the owner's manual but can't find the felt plug or outlet pipe on my VH oil tank....Any photos or links to a photo?...Thanks Will.
PS: Oh I just thought...I've probably got the wrong oil tank fitted I bet!

[simon.holyfield]

If you have a close look at the picture, you'll see a small hole below the hole where the strainer fits. That's the feed to the chain oiler, and it goes down to the bottom of the tank to connect to a tube to the FERC with a rubber connector. There's supposed to be a felt plug in it to meter the feed to the FERC.

Perhaps the felt plug is missing?

[will_curry]

There should be four outlets at the bottom of the tank. Two have connections to the
engine. One of these, the return to the tank, has a small branch which feeds the rocker
box. The fourth will look like the third but comes straight out of the bottom of the tank.
This is the feed to the secondary chaincase and the potential source of oil.

If your tank doesn't have this fourth outlet it's from a 1954 or 55 bike.