Roller bearing

[John Armstrong]

Having a tinker with the bike post 2500 miles in two weeks, and before the trip it had a period of venting gearbox oil into the driveshaft tunnel as the notch didn't have any sealant on it. So I thought I'd see how the sealant was bearing up, and so undid the rear gaitor and drained off a tablespoon of oil =

Then had a look inside the tin and saw one roller bearing roller It measures 6.38mm by 2.5mm diameter. Tried turning the rear wheel and it doesn't feel graunchy to me, and had a peek at the UJ's through the front gaiter and nothing obviously amiss.

Nothing really noted that when warm ie after a couple of hours cruising at 70 mph in 30 deg c heat there seemed to be a gruffness at 3500 in top, but that might be due to the engine etc getting up to / close to over temping. And that happened in the first 500 odd miles.

So from those who've had the "pleasure" of pulling apart para drive shafts and the UJ's, is it one of them?

Piccy of the offending item below:

 

[MickDB1]

I recon its a roller from yer pivot on yer bevel box
Mine was knackered when I took it to bits after finding the same

 

[John Armstrong]

I recon its a roller from yer pivot on yer bevel box
Mine was knackered when I took it to bits after finding the same

Without stripping the bike into a 1000 bits, is there any easy way of checking to see how it is?

 

[MickDB1]

Wish I had measured one of the rollerpins then we may have made a more definate dyagnosis
they are in a flimsy basket/cage

Wait a while for some proper expert opinion but
I removed back wheel chocked up paralever and suported bevelbox
remove the ruber cap and warm with a hotair gun the threadlocked locknut on one side and the 12 mm allen keyed nut on tuther ( that one is super tight with locktight ) remove one at a time and inspected = one had dropped to bits

I would get a set of new uns on order and do the job anyway - dont think they cost that much about 15 quid

Like I said wait for another opinion though John

HTHY

 

[John Armstrong]

All usefull information

I noted a slightly strange suspension feel when the rear suspension was at full extension. Am I right in that its bearing #4 on the piccy below:

 

[neil p]

Hi John,
I have just today had the same experience on a ´91 80GS.
I first noted a oily dampness on the back gaiter clamp and when i opened it got an egg cup-ish of gear oil. Bevel level OK, gear box down slightly.
I have only had the bike a few days and am still going over it, like you do.
So i really don´t know for how long its been collecting.
I am assuming the gear box output shaft seal is a bit tired ?, or is a bit of seeping ´normal´ !! Do you think its more likely to weep in hotter conditions, because its upto 35+ degrees in sunny Andalucia at the moment.
I imagine the seal is something i will have to sort out soon.
It also got me thinking about how the paralever UJ´s are greased and if the splashing oil would damage them. The shaft turns smoothly and the front UJ looks good with relatively fresh grease visible.
AND THEN, out popped the same little roller from a fold in the rear gaiter
I have for now cleaned it up topped up the gear box and put it back together and will OBSERVE.
I then came in for a beer and a bit of lurking and saw your post.
Great the internet innit !
Are you ok with a tea spoon of oil in the drive shaft tunnel ?
I shall now look for play in the pivot joint.
Changing the bearing on the bevel pivot doesn´t sound to bad, the gear box seal is a bit more committed.
Does the gear box have a vent ?

 

[MickDB1]

Yes John no4 and no12 are the suckers
I hope
with regard to the other guys post
the gearbox seal has a tiny vent hole in the top of it
I wouldnt change owt - just keep an eye on it
They all do that sir is a popular statment to an eggcup full of oil in the gaiter

HTHY

 

[neil p]

Hi Mick,
Thanks for the advice.
Is this the same notch that john has put sealant in ?

 

[Voyager]

The notch in the casing around the rear output shaft oil seal should be filled with silicon sealant, or similar (I use Blue Hylomar gasket sealant).

The Monolevers have oil in the drive shaft and don't mind a bit extra from the gearbox - so the vent is left open for them.

The Paralevers run dry (propshaft splines are greased) and so don't want gearbox oil down there (probably not going to cause much damage if some gets in, though).

Paralever gearboxes breath through the hollow 6mm bolt that retains the speedo cable in the top of the gearbox and also has the battery earth cable under it.

Bob.

 

[John Armstrong]

Hi Mick,
Thanks for the advice.
Is this the same notch that john has put sealant in ?

Hi Neil

Probably. The mono and para gearbox's are AFAIK the same, but the notch is meant to be open for the wet running mono drive shaft but closed for our dry para's. Before the sealant fix there was a lot more fluid coming out. I'll have a search to see the piccies that tell the tale better.

This thread is one I was thinking of: http://www.ukgser.com/forums/showthread.php?t=23925

 

[neil p]

Thanks John,
Interesting link.Tomorrow i´ll look for the notch..............i´m sure the high air temp. and running temp. has got lots to do with the oil expanding.
Looks like i´ll be changing the roller bearings ASAP.......

 

[Sylvester]

John, changed my wobble box bearings last year. I couldn't say if the rollers were that size. I can't think of anything else in that area. I can't see how the roller could escape without some other form of notification. I'd tear down the back end anyway, I would not like to experience a failure in that area. I had to use mucho heat to get the pivot pins out and buggered up my favorite hernia bar in the process. They were really tight!!!

 

[John Armstrong]

Going to disconnect the para lever and shock absorber, remove the rear wheel and see if I can feel any notchiness in the pivot. My guess is with everything connected, then you'll only feel something when its catastrophic

 

[Beemerboff]

I ran 35000 km with oil in the paralever, plus whatever mileage the PO did, and no damage, so no panic on that account.

The roller is another matter.

The rollers are held in place by a flimsy plastic cage, and if/when that cage breaks up total failure is quick and it can trash the paralever case too.

So probably best replacing the bearings when you have them apart no matter what you find.

 

[John Armstrong]

Annoying that the roller could have been there 2000 miles or 2 miles

Better to have found it though before too much damage, I hope

 

[neil p]

Hola John,
Please let us know when you find where that roller came from, and how it all came apart. Good Luck .

 

[John Armstrong]

Hola John,
Please let us know when you find where that roller came from, and how it all came apart. Good Luck .

Will do. Last night I took the rear wheel off, disconnected the paralever and shock absorber and wiggled the bevel box about. No obvious graunching, and couldn't see any obvious damage on the outer of the bearings when looking down the driveshaft tunnel. Bit busy over the next couple of weeks so wont have much chance to rip the back end apart even further.

 

[Voyager]

Confirmation I Think

I had a rummage in my 'used parts tin' and found an old, damaged Paralever Bearing.

I took it apart and measured a roller . . .


Length = 6.39mm.

Diameter = 2.48mm

So, it looks as though the loose roller came from the Paralever bearing as suspected


The rollers are held in a rather flimsy nylon cage (I damaged mine by mis-aligning the pin when threading it back in ).

The cage is retained by a lip around the outer track. The bearing would have to be very slack / worn to allow a roller out if the cage was to break up. In other words, there should be some noticeable play in the paralever before the rollers start escaping.

This pic shows that the roller is wider than the visible part of the nylon cage.

If there is no noticeable / detectable play, I would suspect that the roller has been left over from a previous repair (wishful thinking, I know ).

Hope this helps.


Bob.

 

[John Armstrong]

Thanks Bob

As much as I hope I can't see the bearing has decided to make a break for freedom after 3 or 4 checks for oil in the rear gaitor

Also if only one has gone then it won't be too graunchy I guess ....

 

[John Armstrong]

The "bearings" are now out, will take some piccies tonight. One was completely fcuked, the other was almost. The plastic roller bearing holder seems to me to be the weak point.