Burman GB gearbox

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john.whiting
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Re: Burman GB gearbox

Postby john.whiting » Sun Dec 02, 2018 2:43 am

You cant really say anything for sure about a 70 year old gearbox......were the original spec bushes sintered or solid?.....what kind of sinter.?are the replacements four owners back bought off Joe Bloggs with the little lathe any good?..bet they arent sintered....Do the solid bushes have properly cut oil grooves?...So making pronouncements about oil dont carry any weight with me,unless you can prove the box was rebuilt to OEM spec,the level was kept up,and the bike wasnt abused in such a way as to fill the gearbox with steel chips .....I might add the first bronze bush I ever made was the top cut off a Binks 2 jet carby.

Graeme.crawley
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Re: Burman GB gearbox

Postby Graeme.crawley » Sun Apr 07, 2019 5:54 am

I recently bought an R65 BMW which has no drain level plug so was happy to find the right amount of oil to put in the box clearly there in the manual. Not lucky with the GB box where Waller and Pitman are silent and this forum has only a couple of references which were all "about a pint". I have always used SAE50 engine oil but recently the sleeve bearings have been giving a lot of trouble so after the 3rd instance I have just added some Slippery additive from Nulon - testing underway soon!. Anyway I put in a pint (570ml) but I can report that when the bung is unscrewed on the oil level it is fully covered by oil so the amount seems to be a somewhat less than a UK pint - maybe it was an American pint that was mentioned! Graeme

Graeme.crawley
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Re: Burman GB gearbox

Postby Graeme.crawley » Sun Apr 07, 2019 6:15 am

To answer the original question - what quantity of oil does the GB box take; I have had a few sleeve gear issues so decided to try some slippery stuff as an additive so preferred to pre-mix the correct quantity so there was none left over to worry about. I put in a pint (570ml) as suggested somewhere in this forum and elsewhere since Waller and Pitman were silent on the matter but I can report that when the oil level bung is unscrewed it is fully covered by oil which immediately runs out so the amount seems to be a somewhat less than a UK pint - maybe it was an American pint that was mentioned in this forum! Graeme

nevhunter
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Re: Burman GB gearbox

Postby nevhunter » Sun Apr 07, 2019 8:52 am

It's hard to knw just what level of oil adequately oils any particular gear box but I would like it to be above the layshaft centre for starters. While the original recommendations were for engine oil there's plenty of manufacturers of gearbox's advice that the new versions of engine oil are NOT suitable for gearboxes that may have recommended them in the past. Similarly aircraft engines that have reduction gears sharing the oil have to have special formulations. Some gearboxes have steel on steel for the sleeve gears and It's critical that they have a hypoid type oil or they will definitely risk seizure and they need more running clearance . Sintered bronze may give a little leeway for oil starvation but they will definitely not carry the load better bronzes will, but will be more critical to lubricate. Just where you locate the oil grooves has a lot to do with what will happen in there also. Nev

Bruce Saunders
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Re: Burman GB gearbox

Postby Bruce Saunders » Mon Apr 15, 2019 11:12 am

While my 54 VH500 (originally NH350) was idling
I happened to push up on the unnder side of the F/drive chain and noticed a noise which I suspect is the mainshaft on the sleeve gear bush bearing. Quess
as the bikes not in gear and running this could be normal
200 miles ago my clutch felt stange and on inspection
had sgeared 3 of the chainwheel bolts.they had beed drilled and lock wired and I had aleady had them out
a few years ago. Replaced most of the bolts Drilled and lock wired again. Didn't notice any play inbthe mainshaft
at that point. Wondering if I should just pull the internals
out and check it. as I know the rest of the bike. but haven't checked the box. Having said that it works well
changes nice if not rushed.selects neutral nice and
oil changes theres no sign of any foreign particles
running Motul straight 50 oil.

john.whiting
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Re: Burman GB gearbox

Postby john.whiting » Mon Apr 15, 2019 12:19 pm

Both Triumph and Norton replacement gear bushes are sintered material,and smaller diameter than the Burman bearings..........if you use solid bushes ,you better keep the oil level up,cause they will seize hard,and lock up the box.

Thoward
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Re: Burman GB gearbox

Postby Thoward » Thu Jul 09, 2020 4:13 pm

Let me start by telling you that Gear Oil’s are not Transmission Oils. Transmissions have gears and synchronisers. These of which require a different additive package. If you are wondering if GL5 covers GL4 the answer isnt simple. GL5 covers GL4 in terms of protection, but contains to much detergent and will strip any white metals and strip any brass synchronisers.

Simply, GL4 gear oils are intended for axles with spiral bevel and hypoid gears operating under moderate to severe conditions of speeds and loads. GL-4 gear oils also have a low detergent level, which help protect yellow and phosphorous metal elements of the gear box. You can use GL-5 for high-speed loads and also for low-speed torque systems without yellow metals.

Putoline GP80 is sold as motor cycle gear box oil and is GL4, 80W.

The Ariel owners guide states use of SAE 50 or 60

If your gear box is seizing up at tick over it is not a cause of the gear box oil, unless you are using 2 stroke oil in it!
Last edited by Thoward on Wed Dec 30, 2020 1:36 pm, edited 1 time in total.

KenGriggs
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Re: Burman GB gearbox

Postby KenGriggs » Sun Jul 19, 2020 8:41 pm

1 pint :D


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