…. also leaking-gearbox

[bernardofeio]

hello

I have a recurring problem that I still didn’t manage to solve in an R100gs

The gearbox leaks…

when I bought the bike the I had this problem but I didn’t know. The gearbox was leaking to the propelshaft housing and I didn’t notice. the result was that I drove with a dry gearbox with the obvious result!

I bought a new recon gearbox from motorworks…. also leaking…. I send it back to UK and the send me another gearbox… also leaking

The breather works ok…

Any other thoughts? which are all the possible leaking places? rear seal?...

thanks!

 

[MickDB1]

Have you made sure
1
the 6mm breather setscrew that retains the speedo drive is not blocked as it also vents the gearbox
2
you are using the proper grade gearbox oil
3
not overfilling it
4
gear selecter seal

HTHY or yer get a bit of good luck soon

 

[brassmonkey001]

Neutral switch?

First thing to do is clean it thoroughly then you'll soon see where the oil is coming from.

 

[bernardofeio]

“the 6mm breather setscrew that retains the speedo drive is not blocked as it also vents the gearbox. “

it’s not blocked… could be the plastic piece were the speedo connects?


“you are using the proper grade gearbox oil”

EP90…

“not overfilling it”

I guess so!

“gear selecter seal”

It’s leaking to the rear. I would say that the oil is leaking from the rear shaft seal, passing thru the gaiter and dropping into the exhaust box

 

[brassmonkey001]

You are checking the gearbox level and having to top it up regularly I assume?

 

[(RIP) Bin Ridin]

Is there a wee hole in the output shaft boss casing that has to be blocked with silicone....or am I dreaming...?

 

[brassmonkey001]

Is there a wee hole in the output shaft boss casing that has to be blocked with silicone....or am I dreaming...?

Ah, isn't that something to do with converting a mono box to a para, or vice versa? I could really do with knowing about this one myself as I'm going to put a mono box on my paralever so I need someone knowledgeable (Rob Farmer or Voyager, I'm looking in your direction...) with some confirmation of what's involved.

 

[bernardofeio]

"You are checking the gearbox level and having to top it up regularly I assume?"


yes... and removing it from the propelshaft housing

 

[skywalker]

If its a paralever gearbox it should have the hard brown seal installed with the flat surface of the seal facing you unlike the mono lever gearboxes which are fitted with the green/blue seal which is installed the opposite way round so you can see the spring on the sealing lip of the seal.
Paralever boxes must have the small "V" shaped hole in the casing of the output flange blocked off with silicon, all others left as normal.

 

[Voyager]

If its a paralever gearbox it should have the hard brown seal installed with the flat surface of the seal facing you unlike the mono lever gearboxes which are fitted with the green/blue seal which is installed the opposite way round so you can see the spring on the sealing lip of the seal.
Paralever boxes must have the small "V" shaped hole in the casing of the output flange blocked off with silicon, all others left as normal.

Brassmonkey . . .

Like the man said

Bob.

 

[bernardofeio]

thanks!

I will try to fing the "the small "V" shaped hole"....

do I need to take the shaft housing out?

any photos?

 

[brassmonkey001]

If its a paralever gearbox it should have the hard brown seal installed with the flat surface of the seal facing you unlike the mono lever gearboxes which are fitted with the green/blue seal which is installed the opposite way round so you can see the spring on the sealing lip of the seal.

Why?
It's still the same output shaft so nothing changes there, why do you need to disturb the seal?

 

[(RIP) pastyman]

According to Haines, BMW went to some lengths to ensure oil from the gearbox did not enter the propshaft hence the new type of oil seal. As has been said it faces inwards and has a spiral design on the lip which also should be formed on a mandril before installing.It also says that the v cutout should be sealed.

 

[brassmonkey001]

According to Haines, BMW went to some lengths to ensure oil from the gearbox did not enter the propshaft hence the new type of oil seal. As has been said it faces inwards and has a spiral design on the lip which also should be formed on a mandril before installing.It also says that the v cutout should be sealed.

So it's a supersession then? I.e. the old type seal is no longer to be used even in mono boxes?

 

[(RIP) pastyman]

No. As far as i can see , its one seal for the twinshock and mono, where there is oil in the swingarm and the other type for the para where it runs dry
but I am no expert.

 

[brassmonkey001]

No. As far as i can see , its one seal for the twinshock and mono, where there is oil in the swingarm and the other type for the para where it runs dry
but I am no expert.

Ah, so the para seal is better at keeping the oil in the box than the mono seal.
In fact, because the mono spring faces towards the outside of the box I assume it's job is more to keep the driveshaft oil out of the gearbox than to keep the gearbox oil out of the shaft housing?

 

[Kenny]

But he is on his third, same problem on all, gearbox's......two of which re-built via motorworks so that seal should be OK !

bernardofeio, they shouldn't leak but many do weep a little and this collects in the gaitor as you state.....just how much oil is coming out of the gearbox ? If it is just the odd table spoon or so every few months, then nothing to worry about

 

[B Murr]

I had a recurring leak from gearbox on a 91 R100GS i had a long while back. Turned out that the leak was apparantly being caused by the frame being misaligned with the swingarm/shaft housing. The bike had been in a crash and this misalignment was causing the shaft to put pressure against the seal I think a shim realigned the swingarm and corrected the problem. All this work was done by a BMW dealer at the time so I didn't personally see the work done myself. In some ways that makes no sense to me as I thought the shafts joints wouild compensate for any misalignment but that is the story I was told at the time.

 

[(RIP) pastyman]

Very strange one this. It is odd that motorworks, who I rate highly would supply three duff gearboxes . were these boxes rebuilt or just second hand replacements, if they were rebuilt, are they paralever boxes?
The only place the oil could come from to end up in the swingarm is through the seal at the back of the gearbox. .

 

[cookie]

The only place the oil could come from to end up in the swingarm is through the seal at the back of the gearbox. .

or from the bevel box perhaps?