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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: K75user1979 on May 26, 2024, 11:12:19 AM

Title: Weeping oil
Post by: K75user1979 on May 26, 2024, 11:12:19 AM

Good day forum

After my Sunday cruise, got home and noticed oil weeping between transmission and clutch housing.   I have seen this before and had to top up about 100ml of transmission oil lost over roughly a 1000kms.   It seems to be getting worse more quickly..  is it something I can just leave for now as it's not dripping at all on the ground or should I attend to it ssoner than later? 

I do have the Clymer manual so will refer to that for any work to be done.   

Thanks in advance.







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Title: Re: Weeping oil
Post by: frankenduck on May 26, 2024, 11:39:43 AM

If it's the transmission input shaft seal leaking then it can foul your clutch plate. (Or, in my case, fowl the clutch plate.)

You're better off dealing with it before that happens.

Title: Re: Weeping oil
Post by: Laitch on May 26, 2024, 11:43:07 AM

My Brick had an oil leak from that weep hole. It confined itself to a few drops a night onto the shop floor. It wasn't smeared around the cases like yours. I rode with it for 10,000 miles until I detected the clutch slipping during hard acceleration at expressway speeds. After that I rode it for another couple of thousand miles; replacing the output shaft o-ring stopped the leak. The clutch disk was oil-soaked and about worn out of spec so I replaced it, too.

If you're doing the work yourself, using Chris Harris's multi-episode YouTube video as a supplement with your manuals could possibly be helpful. He's working on a K100 but explains its differences with the K75 as he goes along.

https://www.youtube.com/watch?v=HZJdZ1HszkA (https://www.youtube.com/watch?v=HZJdZ1HszkA)

Title: Re: Weeping oil
Post by: frankenduck on May 26, 2024, 02:53:17 PM

Is it motor oil or gear oil from the transmission?

Gear oil smells like sulfur/rotten eggs.

Title: Re: Weeping oil
Post by: K75user1979 on May 26, 2024, 03:53:10 PM

I just ran my finger over the oil on the underside, oil is pitch black which is strange as I change the oil way sooner before it can get that black.  Engine is losing no oil although maybe an imperceptible amount on the sight glass due to it being more of a weep.   I definitely had to top up trans oil a little while back, will check the level now with the special tool in the bag to see if it's dropped again.   

Title: Re: Weeping oil
Post by: K75user1979 on May 26, 2024, 03:59:09 PM

I've watched quite a few of Chris's videos, will definitely give it a watch before attempting any work, thanks Laitch.

 

Title: Re: Weeping oil
Post by: K75user1979 on June 01, 2024, 10:50:12 AM

Got around to removing the alternator and starter motor in order to locate more precisely where the oil is leaking from.
Appears to be coming out at the right of the alternator dog spinner thingy, not sure of the correct lingo here. 
Assuming there's a seal behind the dog drive which after removing the dog I can just pry out and replace?

I've been searching this issue now and seems quite common.   Anyone chime in before I stuff anything up.. will appreciate any hint tidbits.

Ok so I got the bolt off by jamming a piece of wood between dog and casing. 

What surprised me next was that the drive dog just slid out with a bit of wiggling..  read that one needs a puller and was thinking about fabricating a custom puller and the thing just came off easily.

I can now get the seal out..

Seal popped out using a small Allen key and levering against the spline shaft and under seal. 






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Title: Re: Weeping oil
Post by: Laitch on June 01, 2024, 12:26:06 PM

Quote from: K75user1979 on June 01, 2024, 10:50:12 AM

Appears to be coming out at the right of the alternator dog spinner thingy, not sure of the correct lingo here.

From MaxBmw's (https://shop.maxbmw.com/fiche/DiagramsMain.aspx?vid=51739&rnd=09082020) parts fiche.
(https://www.motobrick.com/gallery/4/1601-010624121427.png)

Title: Re: Weeping oil
Post by: K75user1979 on June 01, 2024, 04:07:02 PM

Thanks Laitch.  Will pop down to my local bearing supplier and pick up the seal.   The alternator spins quite free apart from a rubbing sound and some restance, expect those are the brushes.  I'm going to dig into the alternator and starter since I have them out of the bike, maybe replace bearings if need be.