Hello everyone, On my 1965 B40F, some months ago I removed the gas tap which the previous owner had fitted on the oil feed, and replaced it with standard rubber pipe. I was aware when I did so that there would be some wet sumping in future, but thought that would not be a big deal. (The previous owner had explained that he fitted the gas tap to stop the wet sumping because he found the bike hard to kick over when it had been wet sumping - he had a bad hip.) Recently the bike has developed a bit of a leak, which I see as a drip coming from the lowest point of the offside footrest, and a drip appearing on one of the four studs/ nyloc nuts on the sump cover plate (I tweaked the nuts a bit tighter, as they're not very tight, but it doesn't seem to have cured it.) It's very slow. I had a quick look , couldn't see where it was coming from, so thought I'd look at it later when I have sorted other things. In terms of quantity, I guess it leaked maybe a mugfull over a couple of weeks, but I'm not very sure. I couldn't understand why the leak had appeared out of the blue, the bike not having been used for a few weeks and rarely anytime. One thing I wondered about was whether the almighty heave and clatter necessary to get the bike on it's centre stand might have jarred a seal loose somewhere. Anyway, this morning I put the petrol tank back on the bike, with a view to trying to start it now that the ammeter and throttle cable have been renewed and the battery charged. But I thought that before I tried to start it I'd better just check the oil level. The way I usually check it is with a steel rule, looking for it to be about 2 1/2 inches below with rim at the top of the tank (where the cap fits.) It was 5 inches below the rim, so 2 1/2 inches below the required level. Mmm, I thought, I guess that's due to wet sumping and the leak. Not being sure how much has leaked into the drip pan, obviously I don't know how much oil the tank and the sump together are now holding. I guess I would need to drain the oil and refill to be sure? In which case, how much oil would be left in the bottom of the sump after draining? Just about a cupfull?
I wonder: is there any way the wet sumping could be linked to the leak? I'm guessing not.
Any thoughts on any of the above would be much appreciated. Thanks. Phil. PS Life is never simple with an old bike, is it?!?
Hi Phil,
Welcome to the world of wet sumping BSAs!! The gear driven pumps which are in use in most, if not all, BSAs are prone to allowing oil to slowly leak through and into the sump - you might reduce it with a new pump but I doubt it would stop it completely.
I also have taps fitted in my oil feed lines which I use to prevent this but have to make certain that I never forget to turn them on before starting the bikes. There are also some spring-loaded demand valves that can be used in the same fashion that open automatically when the pump pulls the oil through.
In practice there's always some risk with anything like this - forgetting to open the tap or an automatic valve failing to open and bike owners take various views on the subject.
I've only forgotten once, on my M21 and then only for a few minutes. Fortunately as it has a roller bearing big end no harm was done. If it had been the A65 it would probably have caused significant damage to the white metal big end bearings that require a constant feed under presssure.
So it's a matter of choice really whether to fit anything to counter the wet sumping or not. If you don't then I'd recommend draining the sump and pouring back into the tank before you start the bike if it's been stood a while as apart from making it harder to start you also risk forcing oil up past the rings which will result in a lot of blue smoke and could also cause the rings to gum up in their grooves over time.
I suspect that the new leak might be related to the level that the oil has reached in the sump after being stood for a while and finding an escape route through bush or bearing into the outer cases.... I'm not familiar with the innards of the B40 - but will be soon as I'm in the process of acquiring an SS90 project :)
Cheers,
Bernie
Good morning everyone, Me again, from a cold but sunny Devon.
I didn't realise, months ago, when I removed the tap on the oil feed, that oil might find its way further than to the sump, ie to the outside. I thought the only issue would be that it would be a bit harder to kick over. So anyway, I guess it might be wise to fit a tap. Any recommendations for a straightforward tap? (for interest I have attached a photo of the gas tap that I removed.)
If oil has leaked to the timing case, does that mean I will have to remove the timing case outer cover to let it out? I'm a bit loath to disturb that unless it's necessary, as I think the seal might be good. Also, the Phillips screwheads have seen better days (see photo attached) - plus I don't have a large Phillips screwdriver! It's not clear where the oil is coming from: it's very slow, but over a period of time a drip appears on one of the sump base filter plate nuts, and a drip appears at the very bottom of the offside footrest. There's no sign of it coming from the kickstart or the gear lever (someone suggested that might happen after wet-sumping.) Any ideas? Maybe it's nothing to do with wet-sumping? But the level in the oil tank is low, so I'm pretty sure wet-sumping is happening - actually it must be because that's why the previous owner fitted a gas tap. I'm just not sure whether wet-sumping is the reason for the leak(s) to the outside. I guess I'll drain the oil from the tank and then see how much comes out when I remove the sump filter plate.
Also, if it has leaked to the timing case, does that mean it might also have got into the gearbox?
Phil.
Update following my email from this morning: I drained the oil tank - there was 1 3/4 pints in it. I took off the sump filter plate - about a pint came out. So 2 3/4 pints in all. I guess with dregs in pipe etc, you could round it up to 3 pints. The bike takes 4 pints. Where, I ask myself, is the missing pint? Some has slowly leaked out, as previously discussed, but not much - I'd have guessed about a mugful. Could the rest be in the primary chaincase and/or the timing case? Or in some other place? Any thoughts would be appreciated. Also, please see my questions in my previous email. Thanks very much for your help. Phil.
PS The good news was that the sump filter was very clean. Also the oil tank filter (just a tiny bit of fluff there.) So I was pleased about that.
I use an 8mm ball valve as the tap with just enough 8mm copper pipe sticking out to get a good seal onto the hose - maybe 25mm or so.
Something like this: https://www.screwfix.com/p/mini-ball-valve-8-x-8mm/26184 (https://www.screwfix.com/p/mini-ball-valve-8-x-8mm/26184)
Now, I've only had my B40 for one day so more experienced owners please correct me if I'm wrong but I think you'll find a crankcase drain screw on both sides. The primary side should have oil in it for lubricating the primary chain and the timing side shouldn't. I doubt the oil will get into the gearbox - if you had a leak past the gasket there it's more likely that gearbox oil would leak out into the crankcase. If in doubt, drain both sides and then refill the primary to the correct level.
I use an impact screwdriver on the original cross-head case screws - they're cheap enough to buy and, if used correctly, will help shift the screw without munging the slots. I replace mine with Allen (hex head) screws which are readily available and much easier to torque up without damaging the end.
Cheers,
Bernie
Thanks Bernie, but (being a bit dim where these things are concerned) I'm not quite sure how I'd fit that. What I have at the moment is the oil tank filter (see photo) screwing up into the oil tank, with its male thread sticking out below, onto which screws the female of a union (see other photo.) That union has a metal pipe at its other end, and the rubber pipe is attached by something like a jubilee clip. I think the internal diameter of the rubber pipe is probably about 1/4" - I can check of course. I'd like to keep that filter and fit a tap somewhere below it somehow. Any thoughts anyone? Phil.
Sorry, correction: int dia of rubber pipe is about 8mm, as Bernie thought. Phil.
I think the leak which showed and a drip at the bottom of the offside footrest was coming via the gear lever after all. I saw a drip on there ( having somehow missed it when I looked earlier.) From what I can gather from talking to people, and from reading R.Ratio, it seems that wet-sumping may have resulted in the timing outer case taking in oil via the hole which is designed to return oil from there to the sump. If the level in the sump is higher than that hole then of course the oil will flow into the case rather than the sump. Then when the level reaches the gear lever, out comes the oil.
Still don't know where the oil slowly dripping from one of the sump filter plate nuts was coming from.
Anyway, I guess I need to fit a tap. Any further advice on that please? (please see my description above of my current set-up.) Is there anything that doesn't need soldering (I don't have the kit)?
Phil.
I'll have a look at mine when the workshop has warmed up a bit! However, on all my other bikes, I've managed to find a place in the flexible feed hose (important to get the right one!) where I could cut out about 60mm or so to allow me to fit the tap in a place where I can get a finger onto the lever to operate it.
The type I mentioned earlier are compression fitting so you just need two short lengths of 8mm copper pipe which you can fit into the tap on the bench using the supplied olives (rings). Tighten but don't overtighten and then fit the assembly into the line using two hose clips. If there is an arrow on the tap showing direction of flow then fit it with the arrow pointing down (away from the tank).
Cheers,
Bernie
Oh okay, they work using olives - sorry to be so slow. Thanks very much Bernie, I'll order one. Do you also use PTFE tape on the ring? Or does PTFE tape not like oil? Phil.
You shouldn't need any tape on a new tap - make sure that the pipe is perfectly round though - it's easy to flatten if holding in a vice to cut to length. Also, make sure you remove any burrs and blow out the copper swarf before fitting.
Okay, thanks Bernie. I'll get some 8mm or 5/16" copper tube. Would you say 18 gauge?
Hello everyone, Looking to fit a tap to my B40 in order to cure the wet-sumping, I have now got the tap (neat little tap, thanks again Bernie) and am waiting for copper pipe to arrive. The copper pipe is to fix (with olives) to each end of the tap, for the rubber pipe to to fix to, so about an inch of copper pipe will be sticking out of each end of the tap. I have just offered the tap up to the existing rubber pipe to see how I would be fixed for space. There's not much room. Please see (poor quality, sorry) photo attached, which shows the current (no tap) arrangement, with the tap held up alongside, to give an idea of size and space. Coming from the underside of the oil tank will be:
the male thread from the filter;
the fitting which screws onto it (over an inch of that goes into the rubber pipe);
a bit of rubber pipe long enough for the pipes from the above fitting and the below fitting to go inside, so say two inches in all;
the tap (a good two inches long);
an inch of copper pipe sticking out below that for the bottom rubber pipe to fix to.
So where the rubber pipe goes onto the bottom of this arrangement will be well over five inches below the oil tank, so it will be in a pretty confined area, and I think might need a pretty tight bend in the bottom rubber pipe, which I guess is not a great idea. So I'm wondering if this is feasible or not. Any advice please anyone? There must be a good few B40s around with taps fitted to the oil feed? Phil.
PS The other photos are of the filter(which I'd like to keep) and the new tap alongside the old tap (which the previous owner fitted and I removed.)
Hold on, I think I'm being stupid.
It dawns on me that the top, short bit of rubber pipe I was thinking of need not exist. I guess the tap can be fitted straight to the tube which comes from the fitting that screws onto the filter (using the olive.)