Leaky Gearbox

[Supershooter]

I’ve had a dirty oily mess where the gearbox mates up to the motor. It hasn’t been getting any worse, as far as I could tell. I’ve decided to refresh the bike, I’m at the point in the disassembly process, I removed the gearbox from the motor. As I removed one of the bolts a few drops of water came out of the hole when I removed the bolt, kinda freaked me out. I kept going and removed the gearbox. Upon further inspection, I noticed what looked like a wet oily spot on the gearbox cover. I’ve looked through the service manuals I have neither address the spot that seems to to be leaking. I’ve circled the wet spot. Is it possible for this to leak, if so how do I fix it?

[mw074]

 I bought a brand new K bike that had to get a new engine put in at 900 miles due to porosity of the block. The dealer knew of several
other cases of this happening when rear main seals were replaced but did not fix the leak. However, for this to be the case on an "85 that now shows up would be unusual.

[volador]

Highly unlikely that circled spot is leaking oil. That boss is the location of the pressed in post for the detent lever/arm on the opposite side.
If after 35 years the area has developed a stress-crack then conduct your own test to verify leak.

Drain the gearbox
Clean the suspect boss outer surface
Fill with enough motor oil like 30W/40W to bathe that cover plate with gearbox standing up or angled to point of the boss
Put it somewhere hot like your boiler room
Wait a few days and see if you have a leaking boss

[Martin]

If you suspect a crack try an automotive shop that does engine and cylinder reconditioning. They should have crack detection equipment. You can also buy crack detection spray cans usually 3 or 4 cans around $90.00 Au probably cheaper in the US. Dymark and Rocol are two of the Brands, but there are more around.
Regards Martin.

[daveson]

 Petrol (gas)  sometimes gives you a quick answer to find if it's a leak between the plug and case,  or if it's case porosity. Back when I was on acres,  I have a memory of certain tractors with case porosity being sealed with a coat of epoxy, on the outside, which wouldn't be seen in this position.

[Laitch]

I’ve had a dirty oily mess where the gearbox mates up to the motor. It hasn’t been getting any worse, as far as I could tell. I’ve decided to refresh the bike, I’m at the point in the disassembly process, I removed the gearbox from the motor. As I removed one of the bolts a few drops of water came out of the hole.

By the mess wasn't getting any worse, are you implying that whatever was making the mess stopped making it? If that is what you mean, if it were my moto I'd clean up the mess and move on.

What was the function of the bolt that was removed from the hole that seemed to leak a few drops of water—to fasten the transmission to the intermediate housing? If so, I'd forget about it. There is no aquifer connect to those holes.  Please clarify.

[The Mighty Gryphon]

If you want to see if you have a crack try this:

Wipe the area with an absorbent cloth to remove the surface oil and dust with talcum powder.

After a minute or so, very gently blow the excess powder away.  Any cracks will show up as dark lines in the powder.

[johnny]

greetings...


flex_seal_liquid_rubber_pint_black-1000x1000.jpg (33.62 kB . 576x576 - viewed 290 times)

stop the madness... use_flex_seal_liquid_rubber_pint_black_and be done with it...

i use it on all my society of cappuccino craftsmen and dumpsters builds...

j o

[K1300S]

are you sure the "oil" is from the trans and not the engine?   clutch o-ring or RMS very common leaks on these bikes.  makes a mess in the same place as a trans leak..

[Supershooter]

By the mess wasn't getting any worse, are you implying that whatever was making the mess stopped making it? If that is what you mean, if it were my moto I'd clean up the mess and move on.

What was the function of the bolt that was removed from the hole that seemed to leak a few drops of water—to fasten the transmission to the intermediate housing? If so, I'd forget about it. There is no aquifer connect to those holes.  Please clarify.

The mess would be the oil and road grime that accumulated on the underside of the intermediate housing and gearbox housing. The bolt that leaked the water was one of the bolts that secures the gearbox to the intermediate housing.

At this point I plan to drain the oil from the gearbox, clean it, dry it, refill it, and wait to see if it leaks.  My guess it that the water that appeared during disassembly was from washing the bike. I'll keep an eye out maybe i'll see something else as I work on this.

are you sure the "oil" is from the trans and not the engine?   clutch o-ring or RMS very common leaks on these bikes.  makes a mess in the same place as a trans leak..

I'm not sure, but I'll continue with an inspection.

Supershooter