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Burman Gearbox Sealing

Phil Mahood

Well Known and Active Forum User
VOC Member
#1
On behalf of a local B Meteor owner (and VOC member!), can anyone offer tips on sealing up the drive end of the box? Our man is experiencing weapage in that area. The main seal is suspect.

We understand the at the main drive bearing is unique, and therefore sealed versions of it are not likely available. Is there anything better out there these days rather than the standard rubber seal sandwiched between washers? Have to admit its been over 20 years since I've had one on the bench and details are a bit sketchy. Any help is appreciated.

Phil Mahood,
Ontario Section
 

A_HRD

Well Known and Active Forum User
VOC Member
#4
Burman Gearbox Bearing - Sealed

Phil,
And/Or he could buy a new, fully-sealed, special SKF Burman drive bearing from me. (Not expensive). :)
I'm coming to the NA Rally and could bring one.
Peter B
Bristol, UK
 

Phil Mahood

Well Known and Active Forum User
VOC Member
#5
Sealed Bearing

Peter. Thanks for this. First I've heard of it. I'll contact the owner and get back to you. See you at the rally.
Phil Mahood
 

nkt267

Well Known and Active Forum User
VOC Member
#6
On behalf of a local B Meteor owner (and VOC member!), can anyone offer tips on sealing up the drive end of the box? Our man is experiencing weapage in that area. The main seal is suspect.

We understand the at the main drive bearing is unique, and therefore sealed versions of it are not likely available. Is there anything better out there these days rather than the standard rubber seal sandwiched between washers? Have to admit its been over 20 years since I've had one on the bench and details are a bit sketchy. Any help is appreciated.

Phil Mahood,
Ontario Section
Hi.I fitted one of these new seals to my bap box and there is no leak from the drive end..leaks can be a problem from just about any entry/exit point on these boxes,which is most likely why they are part filled with grease..I looked at the Panther owners site(I have a later oil filled box on my Comet) and they suggested using heavy grade gear oil.I now have 140 grade morris straight cut gear oil and apart from a faulty gasket have no leaks from the box(the rest of the bike leaves something to be desired!) Using this oil makes sure that the bearings and bushes do not run dry.If you have ever seen a Burman box with a destroyed layshaft bush you will know what I mean..john
 

derek

Well Known and Active Forum User
VOC Member
#8
I am in the process of re-building a Burman gearbox and have fitted the main shaft bearing seal. But as I intend to run with oil, I am concerned about oil leaking along the clutch drive shaft through the main shaft bushes! Also is there anyway of sealing the selector shaft where it passes through the inner to outer case, as I can see this filling up.
 

Robert Watson

Well Known and Active Forum User
VOC Member
#9
In the middle of doing this to the Two pre war BAP boxes.
1) Peter's bearings plus an external seal fitted to the drive bearing
2) Lay shaft and selector shaft fitted with blind hole bushings so no need for the little tin plates
3) Shorten the k/start shaft outer bush by 1/8 and bore the outer cover to 15/16" X 1/8 deep and fit a CR seal
4) On the CO 54 (gear selector shaft bushing in outer cover) fit an internal O ring
5) CO 90 (Control spindle) fit an external O ring
6) Haven't got to the clutch push rod yet

I think that plugs all the holes. Assemble meticulously

Fill with 80-90 gear oil

Pray

Robert
 

derek

Well Known and Active Forum User
VOC Member
#10
Thanks Robert, All very interesting, but I may try to keep the space between the inner cover and outer cover dry. Therefore having to make just the inner cover oil tight. The clutch shaft that I meant, was leakage through the bushes between the input main shaft and the output main shaft. Derek.
 

A_HRD

Well Known and Active Forum User
VOC Member
#11
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

Active Forum User
VOC Member
#13
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

Well Known and Active Forum User
Non-VOC Member
#14
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

Active Forum User
VOC Member
#15
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

Well Known and Active Forum User
VOC Member
#16
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

Well Known and Active Forum User
VOC Member
#17
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

Well Known and Active Forum User
VOC Member
#18
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

Well Known and Active Forum User
VOC Member
#19
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

Well Known and Active Forum User
Non-VOC Member
#20
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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