Bummer Oil Leak

[mitch89445]

hello
My 03 has a primary oil leak. It looks like its by the oil plug but is wet up behind under the drive sprocket. Makes me think it might be the primary inner cover seal for the clutch shaft. But is darn hard to tell for sure.
It wont leak till its hot . When I stop she drips a couple of drops on the ground in nothing flat. any input greatly appreciated
Mitch

[ElDiablo]

Because some people have never seen this leak they will tell you that I am wrong and they are right.

I am right though as I have seen the EXACT same leak you describe MANY TIMES. Not only that, my 02 model has the same leak.

Here is what I know.

You have THE LEAK!

THE LEAK cannot be fixed by your local HD dealer. They will do up to six attempts to fix your bike. Guess what?

They cannot fix it.

Neither can you.

What is the problem?

Most likely it is case porosity somewhere.

THE LEAK is common enough on DYNA TC88s that you can bet a dollar that HD knows exactly where the oil is coming from but the chances that your dealer knows the fix or will even fix it if they DO know are very, very slim.

Might as well get used to it.

It is possible that you need to replace the main primary gasket. Harley has changed this gasket three times since 2002 so there is a leak issue in this area that they are trying to resolve. CAREFUL installation of the primary cover with the latest gasket might fix your leak if you are lucky.

Just don't be surprised to see the leak again just when you think it is finally fixed.

It is primary oil that you are leaking and I believe that it is case porosity in the outer primary that is the problem. Chrome or not.

I'll edit this to add that no doubt you do have leaking seals at the inner primary and probably the transmission shift shaft seal and output shaft seal.

If a seal replacement fixes your bike you are very lucky.

Let me guess, you have somewhere between 1200 and 2000 miles on your bike?

[Maj]

The first thing to do is clean up the area with a degreaser. The wind blows leaks all over so the source becomes difficult to locate. Many primary side leaks look like they are coming from the drain plug but that is just because all leaks get blown rearward and to the lowest point. Once clean, go for a ride and stop every couple of minutes and inspect for the leak source. Continue until you find the source.

Case porosity is an unusual, but known problem on TC88's. The MOCO can and will fix it under warranty by replacing the leaking case. There's a good tech article on diagnosiing porous TC88 cases in the November American Iron - on newstands NOW!

[lcandela]

I have a 1994 FXD-CONV with an Evo, so this is probably like comparing apples to oranges, but I had an oil leak that I thought was from the primary that sounds just like what you described. As it turned out, the leak was not from the primary at all. Oil was leaking past the seals of the transmission, running down to the back side of the primary case and then running down to the primary drain plug which is the lowest point.
Just thought I'd share my experience.

[The Dane]

Had the same problem as lcandela on my 2000 FXDX. The transmission seal leaked. It's a "normal" failure on many harleys. Our local shop has replaced 3 seals on 2000 and up twin-cams this year.

Oil is running along the sprocket and down the back of the inner primary. At first it looks like a primary leak. Try to smell to the oil, primary and transmission oil smells different.

[mitch89445]

Thanks for the tips
I think my Harley dealer will help me with this one. I hate to take it in but I've done all I can do with out tearing the rear primary cover off and then looking some more.
Mitch89445

[pops]

I had what I thought was a Primary oil leak also. I changed the inner
seal on the output shaft to no avail. I decided to ride for the summer
and tackle it in the winter. One day while cleaning the bike I noticed oil
on top of the engine oil tank on top of the trans (98' Superglide). I stuck
my hand in between the coil and rear cylinder to wipe it down (left side
of bike sitting on it). When I pulled my hand out I had oil on the back of it.
I had bumped it on the lower rocker box cover right under the lowest edge. I had found what I thought was a primary leak. The lower rocker
box cover(three piece affair). What was happening was when I returned
from a ride and parked the bike on the jiffy stand the oil would drip off
that rear most edge straight down onto the inner primary case and drip
off the case near the drain plug and make appear to be a primary leak.
When I removed covers the lower one which holds the rocker arms had
a thin gasket which had cracked right in that corner. The parts dept. at the
told me was a popular problem which was remedied with a replacement
gasket.
This might not be everyones problem since some of the posters have 02
and 03 bikes but the pre Twin Cam motors could be affected.
Hope this helps someone.

[mitch89445]

pops
Thanks for another Great tip. this is what makes this site such a Great wealth of information.
Mitch