G: Gearbox (Single - Burman) Burman Gearbox Sealing

A_HRD

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Lubrication Matters

Derek,

If the bushes are in good condition then there is unlikely to be any leakage at this point because there is (or should be) a helix (scroll) on the mainshaft winding any excess oil back into the box.

If you are going to run the outer cavity "dry", do give all the components therein a liberal coating of grease!

I use Castrol "Spheerol" Liquid Grease in the Burman gearbox. It starts to go runny at little over room temperature but freezes again awhile after stopping having filled all the bushes and gear-teeth with a thick film of lube. Great stuff - and I think you'll find Russel Kemp stocks it.

Peter Barker
 

Don Morris

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I use the Castrol Spheerol in my Burman box and have had no problems with it. There is a slight ooze from the gearchange pivot but no leak from the case itself, but I do have a slight leak around the sprocket end

I have not used gaskets on the cases, being careful regarding end clearances and all is well.

As said by A_HRD it does distribute itself around the box and in the bearings and bushes. When taking other grease filled boxes apart it was common to find dirty grease just around the gears and unused grease packed on the sides of the casing.
 

Tnecniv Edipar

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Although I have a twin I'm interested in this issue as I have a Matchless WD G3L with a Burman boxjust about 2 go back on the road. Any reason y u guy's don't use semi-fluid grease in these boxes ?
 

Don Morris

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Castrol Spheerol is called by Castol 'self levelling' in that sense it is semi-fluid.

As said before when you run the gearbox it thins out and spreads all through the gearbox, unlike soap loaded greases - which is the common type of grease.

Other companies make similar greases which they say are oils thickened by polymers.

Spheerol has been used by many people and no adverse reports have come my way. Certainly try the Spheerol it works for me and the gearchange is smooth and easy.
 

Robert Watson

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I think the problem you may find with that approach is that the slector shaft runs on 12 little roller in a steel sleeve in the inner cover, but these are right at the outside end of the cover so tough to seal and keep lubricated, except of course by going out and really thrashing it and getting the gearbox hot enough that oil gets up in there if it is sealed from the outside!!
 

Tom Gaynor

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Lubricating Burman gearboxes

I never had problems with Burman gearboxes, so can't make claims to expertise. What I do know about gearboxes in general comes from lots of experience with Rudge gearboxes. What Rudge gearboxes teach is that gearboxes don't need much oil. The Rudge box contains only just enough oil to allow the biggest gear on the mainshaft (bottom of the box) to put its toe in the water. (They also teach the importance of endfloat to Rudge gear selection which is where my experience comes from.)
The same is true of Norton boxes: enough oil to reach the balls in the lowest bearing is enough.
It strikes me, reading this thread, that what Burman did was use grease to provide a reservoir of leak-resistant lubricant, much of it, as someone has remarked, stuck up in the attic, untouched. If therefore one managed to seal the box completely, the reason for using grease would disappear, and one could oil. This in turn would allow Canadian speed demons, should such beasts exist, to use only enough oil to wet the moving parts, thus reducing drag and increasing efficiency.
 

nkt267

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The 'drain' plug at the rear of the oil filled B A P box is actually a level plug.
Richardson says that the recommended amount of oil in the box is '1.1/2 pints.which equals 1.1/4in on the bottom of a dipstick inserted through the filling orifice'.
I filled my box till the oil ran out of the level plug with 140 grade straight cut gear oil(Morris).
I had to remove the box to repair the adjuster thread(also the only way I could get the valve lifter plunger out) I doubt if I drained more than about 1/2 to 3/4 pint out of it and the whole inside of the box was well lubricated.It would seem to me that so long as the mainshaft gears splash oil round the box all should be ok.I have just sent off for the correct oil seal for the kickstart shaft as I find the felt washer is not good enough.If the box is over filled it will spew oil out of every orifice it can find.Once it has found its own level all seems fine even cruising at 70.
 

Tom Gaynor

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Burman boxes - idle speculation......

Firstly, thanks nkt267, I now know where to get straight 140 gear oil, for use in my Sunbeam worm drive! Who suggested this was just idle gossip?
Sid Biberman avers that filling Vin twin boxes with EP90 makes them feel smoother (EP90 is about SAE40 vis). I've tried it. I can't honestly say I noticed: maybe it's me. I use ATF in Vin and Manx boxes (ATF is probably minus SAE20 vis ) with no problems, and Anyold SAE40 in the Rudge because it's never in there for long.
Renold used to say that putting heavy oil in chaincases was fruitless because the chain just cut a channel in it and remained dry. 'iggins (The Prof) in MPH casually exploded the theory that making an oil bath for cams - the cam would dip into the cooling and lubricating oil on each rotation - was other than a waste of time. When (Volvo?) made one, c/w a perspex viewing rig, it was evident that all the oil was swept out of the cooling and lubricating bath on the first rotation and the cam remained dry thereafter.
Not unrelated: was there a date when Burman changed to oil-filled boxes, or was it oil for some bikes, grease for others?
 

Diogenes

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Burmania

"Not unrelated: was there a date when Burman changed to oil-filled boxes, or was it oil for some bikes, grease for others?"

See paul richardson pp 88 and 219.

And 'The Motor Cycle' page 429 , 1 Oct 1953, to ensure confusion.

























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