Electra Oil Leak

Hi Andrew,

You observe oil coming out of the primary chain case at the point where the three wires exit the inner chain case.

Is the rubber grommet that seals the three wires present? You mention using silicone sealer so I presume it is not. You need the proper sealing rubber part if you can find one. 

If oil is coming out of this hole I suggest the primary chaincase is too full? because the crankshaft oil seal, behind the crankshaft sprocket is defective? and the bike has stood so long that the crankcase is holding all the engine oil? and the the level in the chaincase matches the level in the engine? The primary chaincase is not pressurised unless the crankshaft oil seal has failed.

Excess oil in the engine crankcases is partly blown up to the oil tank by the crankcase breather system, and mostly by the oil return pump. Excess oil gets there if the bike is left standing, unused, for a month or more.

Your bike has stood a long time and I'd suggest the crankcase breather system is ruptured where the rubber pipe fits on the stub tube coming out of the engine above the gearbox sprocket. Oil is being forced out of the engine breather stub tube when you start your engine and going all over the floor. You need to renew the breather pipes (engine to oil tank / oil tank to top of chainguard) as they perish easily and also can be attacked by a slack drive chain. They also have a habit of blocking solid with water/oil emulsion, so best to check they are clear.

Access to this region around the gearbox sprocket is rubbish and easiest when primary inner chain case is removed. You might be able to do it without removing engine sprocket/alternator/clutch. Please use the proper pullers or secondary damage from hammers, screwdrivers and levers will leave your Electra irrepairable. Replacements are not generally available, unlike the more modern stuff you are used to.

I'm sure you will get there in the end. 

Peter

Andrew,

My Navigator leaked in exactly the same way as your when I first got it.   I found that the crankshaft oil seal had hardened with age and was leaking engine oil into the primary chain case over filling it, causing the clutch to slip and pressurising it causing oil to leak past the oil seal behind the clutch and emerging round the gearbox sprocket.   Although both seals are available from the NOC shop for a few pounds unfortunately their replacement requires stripping the whole primary side which requires a special puller to remove the crank shaft sprocket.   Whilst doing the job it is worth replacing the gearbox output oil seal behind the final drive sprocket which if it isn't leaking yet probably will do once you start using the bike!   Remember the nut holding the sproket on has a tab washer and a left hand thread.   Good luck - once these jobs are done it will be oil tight.......from there!     Nick

I'll be interested to see where the leak is and what needs to be done to cure it.

I've been chasing leaks on my Navigator.  Rather than use a proper sealant with the gaskets, whoever built the engine used silicon sealer, just about every joint leaked!   That and poorly prepared joint faces.   I've sorted out the easily accessible joints, tappet covers, timing cover and so on without dismantling the engine,  but I'm left with a bad oil leak around the final drive sprocket.  One of three places then, oil seals either side of the sprocket or the engine breather?

I'm going to ride the bike some more then dismantle the engine, something I intended to do anyway for peace of mind but now a necessity.

Hi Andrew,

Some good suggestions from Nick. 

In the photos you posted 24/7/20.

Insulation on stator. It doesn't look bad to me but I can see you are concerned about the tape coming unwound. On a similar problem on my 1964 Electra I cleaned the stator in petrol. Do it outside for safety. Then got some thick thread, almost quality twine, intended for buttons, and took a few turns around the affected coil. Knotted. Cut off tails. Then using a polyeurethane varnish made sure everything was stuck down neat and dandy. You could use epoxy resin instead of varnish, but keep it thin so that the heat can get out of the coils.

Stub pipe, oil breather, at rear of engine. In your photo the pipe looks as though it is brass. The original would have been zinc plated steel and looked grey. Also the original breather pipe was black rubber, not the vastly better blue silicone pipe shown. I'm just a bit suspicious that the brass tube is a sleeve over the steel pipe, and why? and is it a leak source?

Generally, the state of the nuts, bolts, gasket faces, presence of correct tab washer on crankshaft nut indicates that your Electra has been well maintained and looked after over the past 55 years. 

Lucky you.

Peter

I was surprised to see the primary chain case was unvented, that is to say no breather.  I think the gearbox may be the same.  I don't think that would cause oil links but no harm done in rectifying the omission. 

I've made a filler cap for the chain case with a breather, suitably baffled so it doesn't dribble oil. 

If there isn't a breather for the gearbox I will sort one out for it.

Lovely bit of machining John!   From experience if the crank, clutch and alternator wire oil seals are in good fettle the Jubilee and Navigator and therefore I suspect the Electra don't suffer from pressurisation of the primary chain case so long as you don't over fill it - you need to check but if my memory is right the Electra primary side takes 1/2 pt, just enough to lube the chains and no more - I have settled with straight 20 grade which reduces clutch slip and drag whilst still providing ample lubrication.   Mine has remained oil tight for three years and almost 4000 miles but I always use silicone gasket goo instead of the rediculously thin and difficult to seal paper gasket - the Electra's may be better.   If you look very carefully at the round gearbox inspection / filling plate on the off side of the bike you should see a very small breather hole slightly off set from the centre.   This is all the breather the gearbox needs, but I find it is better to position the inspection plate with the hole upper most otherwise with spirited riding I do get aslight weep from it.    Final top tip is make sure the engine oil tank isn't over filled - the level should be 2" below the mouth of the filler cap.   You need to check that the rubber engine breather pipe vents into the lower of the two pipes short pipes on the top of the tank.   The upper pipe feeds a thin rubber tank breather pipe which routes through a small hole at the top front of the chain guard so any condensed drops of oil lubricate the final drive chain.   I have been surprised just how low 2" is below the filler and how even 1/4 Pt too much oil 'to be on the safe side' means that as you corner the excess oil spills down the breather pipe and appears to be an oil leak from either the primary chain case or gearbox output seal!    Good luck and keep us informed on how the Electra is getting on - Lightweight Twins are remarkably good, reliable and quite sporty little bikes once properly sorted!  

Nick

Have a look at Dave Cormeau's narrative on gearbox breathers - a good piece of experimentation. End result is breather isn't needed as gearbox vents via the clutch cable amongst other 'vent'points. 

Regards, George. 

I've looked for a breather hole in the filler, none there, I'll look for the other hole when I dismantle.  How big is the hole and can its exit been seen while the engine is still in the bike?

I have found and read the article by Dave Cormeau on gearbox breathing.  I'm not sure its a valid experiment, he is not duplicating the conditions the gearbox runs in. 

I would agree that allowing the gearbox to breath is not a cure for a leaking box,would most likely have little or no effect on leakage. There is a good reason to allow air to move freely in and out of the box, he seems to have ignored that.

Hi guys,

Just to say my observations and experience have been the same as Nicholas Clarke and Bruce.

The primary chain case of a Lightweight is vented through a tiny hole in the inner case near the csk securing screw behind the clutch. 

The gearbox is vented through an equally tiny hole in the inspection/filler cap.

When all other seals are sorted the bike runs nicely, and enjoyably, without leaks from chaincase or gearbox. The engine breather that finds its way to the top of the chainguard, via the oil tank, is a fairly generous mist on my Electra, so I don't often feel the need to remove and immerse the chain in LinkLyfe (Remember that!!) .Maybe my Electra is a slightly heavy breather after 36,000 miles on original bore and pistons, but what's a slightly misty rear rim after a few hundred miles.

When replacing the oil seal in the primary chaincase, take care to support the thin wall around the seal when doing it. 

If you rest the inner chain case on it's sealing face and bash the new seal into place, the thin wall containing the seal is belled downwards, so that the seal is closer to the clutch than it should be, and the seal may not even seal on the last part of the sleeve gear, being too far towards the clutch and always leak. Use a straight edge to check the case is reasonably flat in area behind clutch, and correct with light hammering with wood between hammer and inner side of chaincase.

The other two seals mentioned in above replies are in more robust housings.

Hope this is useful Andrew and John.

Peter

Useful info Peter, thanks.  I've found the breather in the gearbox filler cap, small hole isn't it!  No doubt adequate to allow air to move in and out of the box but less than ideally positioned, can water get in? 

I'll look for the primary chain case breather when I dismantle the engine.

I've been considering the crank case breather, that may be the cause of the leakage?  I have some ideas for improving crank case breathing. 

John, the crank case breather on the Electra and late Navigator (like mine) is the same and consists of a metal pipe several inches long, emerging from the rear of the left hand crank case well above the gearbox final drive sprocket.   A rubber pipe runs from it up to the lower (forward) of two small pipes emerging from the top inner side of the oil tank.  Providing the pipe is in good condition I have not known it to be a source of a leak.   As I described in my post above the rubber oil tank breather pipe should be attached to the upper (rear) of the two small pipes and routed down to a hole in the front of the chain guard just above the gearbox sprocket.    With a healthy engine and correct oil level only hot oil mist from the engine should vent via this oil tank breather tube.   Similar to Peter in my experience it is just enough to keep the chain lubricated but not enough to produce anything like the oil leak you describe - they are almost certainly down to leaking crankshaft and clutch oil seals or the gearbox oil seal.    The other possibility is over filling the oil tank as I did explained above - or having the engine breather pipe incorrectly attached to the upper oil tank pipe and the oil tank breather attached to the lower oil tank pipe which has a similar effect.   It took me several months of experimenting and head scratching to fathom it out but I'm not very bright! 

Good luck and let us know how it goes!  Nick      

Nicholas, I'm just speculating as to where the (bad) oil leak is. Its in the sprocket area but I think you are right, unlikely to be the breather.  I did notice a small amount of oil in the clear tube I fitted to the  breather so oily air is passing up through the breather. I've got the breather and vent pies the connected the right way round.  

I think the breather arrangements can be improved, at the crank case and something to encourage separation of the oil and air at the oil tank end as some other manufacturers did. 

But first I need to find where the oils coming from.