Forum

[Bullet Whisperer]

I was under the impression that the neoprene seal was bonded into the worm gear and if not it causes an oil feed problem.

If not, I’d still prefer one over cork (having experienced cork stuff breaking up and failing, or at least compressing over time and causing problems). But each to their own, I suppose.

There is a worm nut with bonded in neoprene seal - which are fine, but the seal can break loose on occasions, causing messy breather issues and very black oil - and this type of worm nut is slightly smaller in diameter than those which take either the push fit cork seal, or a similar push fit rubber seal. The bonded seal is smaller in length than the cork or loose rubber seals and this is how it can cause trouble if it breaks loose. The cork and loose rubber seals, being longer, butt right up tightly to the oil feed quill bolt face when they are pushed tightly into the crank, so cannot go anywhere to cause trouble, although it is worth checking / changing them from time to time.

[Wheaters]

Thanks Paul, useful stuff. I’ll bear that in mind and will probably remove and thoroughly inspect the timing side when I next do a service.

I bought a new oil pump drive shaft some time ago “just because” and will also fit that if there’s any sign of a need. So far, all is good after some quite hard riding last summer and autumn.

[jawa-enfield]

Okay, many go for the bonded seal, some are fine wirth the cork or loose neoprene seal.. (which you slide on the oil feed tube and then mount the lid, to prevent damage on the inside of the seal and loose parts going in the crankshaft?)

I have no idea what was originally in this engine, as there was no seal present..
There were a lot of cork parts on the rocker spindles, but i cannot imagine cork parts going through the big end, and filter, up the oil ducts and in the rocker assy..

[Wheaters]

Is it possible that cork based gaskets were used for the rocker covers in the past? Having said that, if there’s cork material in the rocker shaft housings, it is most likely that it’s come from the main oil feed seal (which must have disintegrated if you can’t find it) and some particles travelled up the rocker feed pipe.....is there any other way they could have got there?

[Conny]

I would think it is entirely possible that fragments of [the missing] cork seal of the oil pump worm could be carried through the return pump from the sump along the oil feed pipe to the rockers and then into the rocker shafts.

I don't see how cork fragments could enter the shaft from a broken rocker box gasket as the shaft is effectively sealed except for the positive feed from the external oil feed pipes.

The fact that these cork fragments are in the rocker bearings seem to me to indicate that they could also pass through the oil pump.

At least that's how I read the situation.

[p]

Right, time to look at the lubrication system:
Some cork which supposing we believe came from the cork quill seal, was found in the rocker oil galleries, that being the fact then consider:

the quill seal is in the timing cover, the timing cover drains to the oil tank, not to crankcase or scavenge pump.
The only oil that goes to the rockers comes from the crankcase,
the only oil that goes to the crankcase comes from the big end feed, there's no other route,
therefore, to get to the rockers it came via the big end feed, directly from the quill into crankshaft gallery, (from the oil tank/pump/quill route it would be filtered), either way it then got fed to rockers by scavenge pump.

The important thing for the op is that if it came from the quill it must have been in small enough bits to pass through big end and also be pumped by scavenge pump to arrive where he found it, so -what would worry me - are there bigger bits remaining inside crankshaft gallery that may quite easily lead to blockage and big end failure in the future?

[Adrian]

If there were bits of cork in the oil supply on the supply side, how did they get past the main oil filter which is supposed to protect the big-end? Check the filter for damage if you haven't already done so, it doesn't appear to have been doing its job.

A.

[jawa-enfield]

Thanks all for the thinking with me and the replies!
Yes, it is a mystery how the cork got there.. i cannot imgagine it travelling it's way from the crank worm sprocket.

I assembled the engine and need to build up courage to build up the bike again. (with the lack of sunlight, i find it very hard to do anything..)
I 'primed' the crankshaft by laying the engine on its side and pouring oil in.. Oil 'dissapears' into the crankshaft so i don't think it is blocked.

An other thing mildly worries me (again); It seems that this bike is an inland-version. Someone told be that it is possible it does not have a big-end bearing.. just conrod directly on the crankshaft. engine was running fine and noiseless though, and no play on the big-end..
Maybe an India-fable?

[Bullet Whisperer]

'Inland version' - ah yes, about as real as a 1965 500cc Bullet ...

[vince]

What is the alternative, outland model, offshore. ??