Transmission seeping oil, need suggestions.

[Ncdan]

Hey guys, this is reference to the 02 Stone I just got and I started a new thread because I figured some of the mechanic minded here would speak up, hopefully. I noticed from the get go that I could smell gear oil however there was no dripping. I cleaned underneath good last night and today went for a 10 mile ride, getting everything good and hot. When I got home I checked underneath and found a small amount of seepage coming from the small rectangular cut out, located just over the oil pan plug, and between the transmission and the motor block. I’m going to venture out of my knowledge territory and speculate that I’ve probably got a leaking main shaft seal.
Input will be greatly appreciated.

[pehayes]

Common leak area.  Anything leaking in the bell housing will eventually drain out that rectangular hole.
Could be engine oil or gear oil.

If engine oil, it could be crankshaft rear main seal, camshaft rear expansion plug, engine breather tube gasket, or bottom two holes of the crankshaft bearing carrier.

If gear oil, it could be transmission input shaft seal, one of the two input shaft o-rings, throwout shaft cone seals.

At nearly 20 years of age, every one of these is suspect.  Crab the frame and fix/replace them all.  Frankly, I'd ignore them all until they got to the nuisance puddle level.  You might start by confirming that neither the engine or the transmission are overfilled.  When in doubt, run both at about 10% low.  In the engine, use 3 QUARTS and ignore the spec for liters.  In the transmission, drain-measure-reinstall but hold back 25cc from the full spec.

Patrick Hayes
Fremont CA

[Ncdan]

Common leak area.  Anything leaking in the bell housing will eventually drain out that rectangular hole.
Could be engine oil or gear oil.

If engine oil, it could be crankshaft rear main seal, camshaft rear expansion plug, engine breather tube gasket, or bottom two holes of the crankshaft bearing carrier.

If gear oil, it could be transmission input shaft seal, one of the two input shaft o-rings, throwout shaft cone seals.

At nearly 20 years of age, every one of these is suspect.  Crab the frame and fix/replace them all.  Frankly, I'd ignore them all until they got to the nuisance puddle level.  You might start by confirming that neither the engine or the transmission are overfilled.  When in doubt, run both at about 10% low.  In the engine, use 3 QUARTS and ignore the spec for liters.  In the transmission, drain-measure-reinstall but hold back 25cc from the full spec.

Patrick Hayes
Fremont CA

Thanks Pat, I sent you a PM👍

[usedtobefast]

I recently went through this with my Quota (very similar power train). 

From what I read and was told, if it is leaking engine oil, very unlikely that will get on the clutch.  So dribbling engine oil you could ignore it for a while.  But leaking transmission oil may end up on clutch plates so that may need attention sooner.  For me, my transmission oil was red, engine oil normal brown/tan, so was easy to see which it was ... plus my transmission oil had a certain stink too it that the engine oil did not.

So maybe a winter time project.   

I would call it a low parts cost very high labor type repair.  I had never done any work like that and I went very slowly, took pictures, etc. and it took me 6-8 hours to pull it apart, then ~2 hrs to "fix" all the potential leak areas (and let all that dry), and about 6-8 hours to put it back together.  Oh, and days of searching & reading etc trying to figure out how to do it!   

Parts are gaskets, seals, and various goops/sealers, again all pretty low priced.  There are a few special tools that can be a bit pricey, some guys borrow these, some improvise and either make their own or make do without (like a special tool to install the rear main seal ... super easy with the tool, but many ways to put a seal in without a special tool).

Seems many guys opt to put in new clutch plates at the same time.  My Quota had 20K miles on it, I replaced my clutch plates and intermediate plate, and the new clutch worked 0% better than the 20K clutch.       I believe it was around $125 in parts, so not a huge expense and I figured why not while I had it apart.

[fotoguzzi]

Smells like gear lube? Then it’s not a main seal. Most likely the push rod seals, the cone shape seals are a know weak spot. Can fix it with a stack of o rings. Need to pull the swing arm but then you can do it in place without pulling transmission out.

[Antietam Classic Cycle]

Smells like gear lube? Then it’s not a main seal. Most likely the push rod seals, the cone shape seals are a know weak spot. Can fix it with a stack of o rings. Need to pull the swing arm but then you can do it in place without pulling transmission out.

This ^^^. Anyone that wants 6 of the "special" sized o-rings for FREE, just send me a PM with your mailing address.

[kfz]

Not changed oil lately have you to fully synthetic?

KEv

[80CX100]

Hey Dan     If it's a "new to you" bike, check to make sure the the previous owner or mechanic had the right amount of gear oil in the tranny.

I know on my CalVin someone obviously decided that if 750 ml of oil was good, then a whole litre jug would be better, I've heard of it happening many times.

The extra oil overwhelmed the seals and caused a slipping clutch, but once I drained the oil, put in just 750 ml and rinsed the clutch plates, it's been running like a top ever since.

fwiw good luck

Kelly

[Ncdan]

Update*****
Thanks Kelly as you may have rang the winner’s bell.
I took the advise of a couple of you guys here and started with the most simplest possible problem and fix. The PO said his Father-in-law did the last service at 7600 miles and new very little else about the subject. So I decided to simple pull the lower lever plug and sit the bike up level and see what happened. I did and as soon as I stood it up the oil came pouring out. I filled between 2-3 shot glasses full of the stinking stuff. Could this have been the issue?
Keeps in mind that it never dropped a single drop on the floor.

[malik]

Quite possibly.

However, although SWAMBO might be relieved, no drops on the carpet means there's no veritable evidence of your superior mechanical skills. You do keep the bike on carpet, don't you?

[Ncdan]

Quite possibly.

However, although SWAMBO might be relieved, no drops on the carpet means there's no veritable evidence of your superior mechanical skills. You do keep the bike on carpet, don't you?

Lol, no Sir but a fine climate controlled basement with it own BooBoo blanket covering at nite:)

[Ncdan]

Nice bike!

Oil seepage, that sounds familiar.
My clutch started to slip with oil seepage. That was when the bike was less then two years old and at 18,000 miles.
A quick clutch wash with mineral spirit and then I changed the oil from 80/90 to 85/140. It saved me a new clutch expense. The original clutch is still fine at 68,000miles and 13 years later.
I use 85/140 in both rear drive and gearbox and make sure I under fill slightly the amount of oil.

85/140 you say. Did that fix the leaking issue also and can you give me the specs on the amounts for the trans and rear end? Thsnks

[Ncdan]

Yes 85/140, and it fixed the oil leak. I thought, who cares if I loose 1/2 a horsepower, let's put thicker oil on that bad Triangular oil seal design. Cheaper then tearing it down to put nice O rings.

-for the trans and rear end, I don't go by amounts, I just fill to the over flow plug and tip some out 
I also keep the engine oil about 1/4" below max..
what do I know

Thanks a bunch for that info and I think I’ll take the advise next week when I change fluids👍

[80CX100]

Thanks Kelly as you may have rang the winner’s bell.

     Well you know what they say, even a broken clock is right twice a day   

     I remember how relieved I was, not having to replace my clutch due to oil contamination, so it's a gospel I like to share
     
     You gotta love it when the cheap easy fixes work.   

     Re the quantities, subject to verification, I think all big block 5 speed tontis take 750 ml in the tranny and 250 ml in the dif (including moly additive if any).

     I'm not young and foolish enough to kick the hornets nest of the subject of gear oil

     Good luck with the new ride, she's a beauty

      Kelly

   

[Ncdan]

Fingers crossed for ya.

Like I said in the other thread my Jackal almost always had a very small weep from the rear main. It made me sad but never made me fix it.

The rear main? So That’s oil right and not differential fluid, right?

[Ncdan]

In my case it was, but in your case it sounds like the transmission input because of the smell. I assume you wiped off some oil and smelled it directly?

Yea kev there’s no doubt the stench is definitely
 differential grease as there’s nothing that stinks that bad😩