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[DM]

Hi my names Dave and I own a 1947 RE 350G......sounds like alcoholics anonymous.

OK, not long had the bike, fully expecting many issues in need of sorting, most I have already done i.e. new piston, rings, oil, filter valve guides and valves.

Thinking I was pretty much home and dry-ish and ready to take her out for a run, I have come across a problem that may need an engine out, strip and major surgery....depending on the excellent feedback I know I will receive from this post.

When static test running the engine there is an excessive amount of oil emanating from behind the final drive sprocket, took the primary case off completely (clutch, sprocket case backing etc) only to find there is no oil seal for the end of the crank. I'm told this is normal and only a rubber bung affair is used, sandwiched between the crank case and primary case backing.

This bung, which I now have and about to fit, wont actually provide a seal that I can see, if anything it will deflect the oil into the primary case.

The first question I have is, should such a large amount of oil be possible to leek from that area? if not
am I looking at replacing the crank bearing / seal...as this may be the culprit?

BTW having a fair amount of oil from the crank case breather as well.

Much appreciate any help, advise......can I sit down now please.

[Mark M]

DM, I know very little about Model Gs but I wonder if your leaking oil is actually a symptom of wet sumping? In other words, if oil is draining past the oil pumps or leaking into the crankcase somehow (there are several possibilities,) you will often find on start-up that it emerges from the breather in large quantity and as you have no crank seal it could also spew out of there too. This is a common problem on Bullets but even the early ones have a simple but effective crankshaft seal which means that the oil usually only exits from the breather or is burnt off as it overwhelms the piston rings! REgards, Mark (and welcome to Enfields Anonymous, 11 and counting....)

[DM]

Cheers Mark M,
Being of the early 70's Honda fraternity I would have expected my RE symptoms to be directly related to crank seal problems. I wasn't sure how effective the RE crank seal was/is. So it most certainly is not usual for this oil gushing from behind the final drive sprocket then?
Wet sumping, yes it definitely is doing that, I'll sort the scavenging side first I think and make a decision from there.

[Mark M]

As l say, not an expert on Gs but l think all the models with pressed steel primary case are a bit incontinent! Most Gs l've seen are quite clean actually so l think your proposed checks and repairs should get the dribble down to reasonable levels! REgards, Mark

[WDCO42]

Hello Dave,
I own a 1942 WDCO 350cc, that is just a bit older than your's, but is quite the same.
There may be a lot of reasons for your leak :
1) The primary chaincase is designed to keep safe your left leg, but not to keep oil inside, so don't expect it to be oil proof... And with age, it is worst (bent inside case in the clutch area, banana look like outside one if tightened too much, etc). I have added on my Co as small oil can that drips oil on the primary chain, at least there is some for some times inside.
2) There isn't a seal on the crankshaft bearing. If you have kept the original roller bearing arrangement, it is not easy to made the mod to have one there.
3) There isn't either a seal on the gearbox bearing. If you have oil in the box, instead of the original grease/oil mix, and been a bit optimistic about the level, the beast will leak there too... So check the oil's colour, to see where it comes from
4) The engine breather valves are just some "grey paper" confettis, that can stick inside the breather "case". if it doesn't work properly, the oil will go out by the engine bearing, poor in the chaincase, and then on the floor... I have made a mod to fit the Bullet's duckbill breather, works good as there are much less oil leaks (there).
5) The G engine doesn't like to have too much oil inside... It seems that the mark on the dip stick is the very high top you can have. I fill the engine to that mark, and let the bike make her own level (sealed left boot, weather proof rear part of the bike, and "interesting" left corners..)
6) You could have too some piston rings troubles, but before going on that way, I'd look at the previous possibilities, especially the oil level and the breather.
Hope it will help you
Claude

[Norm]

Claude I'm just about to put a WD motor back together after it was damaged in a fire and I thought they must have fitted a felt seal on the drive side bearing and that had burnt off, so I got the case machined to take a seal. Haven't tried it yet

[WDCO42]

Hello Norm,

I'm interested, does the inner part of your seal "works" on the shaft, or the sprocket ?

[Norm]

Dave it is running on the sprocket

[DM]

Thanks Guys, Very useful info.
In short, the excessive oil exodus is from the drive sprocket (from crank) and since there wasn't even a bung seal between the primary case backing to crank case, all the oil spewed from crank shaft down the casing to floor.

Now I am fitting a bung / seal, the oil will or should run into the primary case and be retained in the casing...mostly.
I have replaced piston, rings, valve guides and valves....but not attacked the oil pump yet, so there may be a week oil return, although oil is getting to the valve train.

Regarding oil level; when I fired her up the oil level reduced to such an extent there is no witness level on the dip stick and negligible oil in the tank. Who's to say the dip stick and cap I have is original, without knowledge of these bikes I can only assume, in short when I put 2ltr in I can just see the oil level when looking into the tank filler and the dip stick shows half way up.

I'm reassembling later today and setting valve and elec timings, so if still a problem I will attack the pump...with a hammer perhaps!!

[WDCO42]

Hello Dave,

For me, it isn't normal that you have so much oil going out the engine to the primary case. My WDCO hasn't a crankshaft bearing seal (but has the famous bung), and there isn't so much oil going out.
It seems you should have a real look at the whole return pump system, as it seems there is a problem there.
An other possibility : on those engines, you have a front and a rear oil "tanks". If your cases are not properly sealed, the oil can come in the "real" crankcase area, it happened to me once.
I had a look at the manual : the oil capacity is 4 pints.
Hope it will help you.
Claude