Apollogies for raising the leaky geabox topic again but after trawling through previous posts, I still need a bit more advice if that's ok?
The gearbox was working well before I went through the rest of the bike so all I treated it to was some fresh oil before it's maiden voyage today. All the gears (and false neutrals) are still working A-Ok but it seems as though it's managing to leak more than before.
I've filled it with Morris SAE50 as per previous posts and I'm guessing that the non-sealed bearing drive-side is what's helping it to escape around the sprocket. Not wishing to be left out, the kick start is also weeping.
Not wishing to rebuild the 'box until at least winter, are there any tips to help keep the oil in the gearbox and away from the floor? I read an ingenious post about a mix of grease and SAE50 but the thread went cold after that.

Help!

email (option): lee@twowheelstested.co.uk

There isn't really a 'magic fix' for this problem that is present partially because the M20 predated the introduction of modern oil seals and partially due to the layout of the shafts and bearings relative to the 'floor' of the gearbox case.
Leaving the bike on the field stand will make matters worse.
As long as you haven't got a sealed bearing be sure to check the oil level frequently to prevent it falling to 'damaging' levels. Weekly or every 400-500 miles would be my recommendation.
A drip tray or parking the bike outside are probably the best ways to keep the garage floor clean.. ....Ian

email (option): ian@wright52.plus.com

I know what you mean Lee. If I top mine up to the proper level by peering down the filler hole it soon leaks out onto the garage floor, leaving me paranoid whether it is completely empty or just down to the level of shaft bearing.

Does anybody thing it is worth/a good idea to drill a level plug hole in the outer casing?
At least you would know it filled up to that level

email (option): Gasboy@btinternet.com

Hi Peter...On the WD box you should be able to see oil in the filler spout at all times..I noted my mileage and then checked mine every day for a while until it was part way down the spout but still visible...I then had a mileage interval to work from...(for my bike). If the bike is left standing (and leaking) for long periods it is best to check oil levels before use..As is marked on the filler plug of the WD box...'Keep Full'.. . ..Ian

email (option): ian@wright52.plus.com

If you're going to take Ian's recommendation be careful what kind of grass you park it on. I heard that gearbox oil is helpful to Tennessee fescue but can damage rye grass.

email (option): jonny.rudge@verizon.net

Why aren't you all using semi liquid grease?

Semi liguid grease sounds like answer, but who makes it, where can it be bought from, and how do you pour it down the filler?

email (option): Gasboy@btinternet.com

Semi fluid grease is recommended for some Burman box's (Matchless etc) Not sure if it's ok for an M20 box though. It will still wind out through an open bearing! Google 'Morris Oils'. It's a bit tedious to install though. I warm the jug in a pot of boiling water and do a lot of prodding with a stick. Not sure about getting it in an M20 filler though. Perhaps you can boil the grease in a suacepan. But give your wife some M&S spending money first Ron

email (option): ronpier@talk21.com

BSA specified monograde sae 40 for their gearboxes. The sleeve gear and its bushes, third gear and its bush, the layshaft (to lubricate the first and second gear bushes from inside the layshaft) and the inner case layshaft bush are all drilled through to enable lubrication to reach the bushes. Apart from the drillings oil also finds its way directy to these, the layshaft bush in the main case and selector fork shaft and bushes. Also there is the question of correct lubrication to the bearings, gearchange mechanism and other parts.
The specified oil will freely enter all these areas by virtue of its low(ish) viscosity..the same cannot be said of semi liquid grease and I consider that by employing this method, lubrication in some areas is likely to be compromised.
Yet again a solution is being proposed that treats the symptom (oil leaks) not the cause (the lack of a proper seal)without full consideration of the possible implications in the longer term or why sae 40 oil was specified as the lubrication medium in the first place.
Fitting a sealed bearing is the accepted cure for M20 gear box leaks and is proven to work. Once that is done there are no further problems with using the CORRECT specified lubricant and thus ensuring full lubrication to all parts....
As I've said before, if you have a puncture you fit a new tube..you don't strap a compressor to the bike to provide an additional air supply...

...Ian

email (option): ian@wright52.plus.com

As Ian has pointed out previously, when the g/box oil level drops, the first area to be damaged is the last point for lubrication to reach, which is the 4th gear sleeve bushing.

With a leak past the output bearing, low oil in the box allows the 4th gear sleeve bush to run dry and begin to wear against the mainshaft, with the resulting brass fines plugging up the mainshaft oil channels that pass oil through the bushing....which futher restricts lubrication, and the catastrophic "cycle" continues.

From my limited experience I can tell you that the grease/oil mix does not seem to reach the depths of the BSA's 4th gear sleeve bushing once the sleeve wear process has begun....For all other areas of the box, the mix seems to lubricate just fine, but to work its way through the length of the sleeve in sufficient quantity to provide proper lubrication is "a bridge too far"....That is at least what I have found.

I finally acted on resolving the leakage problem and installed the sealed bearing. Now, hopefully the gearbox oil level will be retained.

email (option): teladelujo@msn.com