My buddy took my 98 FXSTS out for a hard ride to see if it was faster that his, and he said, "Hell Yeah!" Now I have a leak from the left rear side of the primary area. I can't really see where it's coming from, but it only leaks when it's running. It's a nice drip.

What can it be?

 

Get a good flash light and follow the oil marks. I had a good drip and thought it was my primary seal and then traced the leak from behind my primary and now just getting the bike back together as I just replaced the trans oil seal. It could be your push rod covers, as some times the O ring at the top leaks sometimes . Could be your base gasket on the bottom of your cylinders... Just have to try to trace it down and follow the oil trail......

 

Yep, could even be the rear rocker box gasket. Doesn't take much oil to spread into a big mess and the way the air moves around a bike in motion, it can move oil from theleaking spot to another place.

one way tobe sure, if you can get your finger to a fresh spot of the oil, taste it. Yes, taste it. There is a distinct difference in the flavor of engine, primaty and transmission fluids.

 

Does you breather exit down to the frame near the primary? Hard running will tend to blow some oil out the breather but only when running.

 

Check your primary case for cracks, especially near bolts holes. Maybe gasket is leaking, check to see if it starts to seep out somewhere . Usually when I get a leak I try to dry everything off first then start the bike and let it warm up, check for leaks...if nothing, then run it a little like a mile or less, then check everwhere again, if still nothing, then go further, etc....I use a lift so you can look underneath the bike real good with a flashlight, otherwise you will need to be on the ground and feel around or use a flashlight and mirror. If it is a cracked primary case it is usually near a bolt hole but around the perimeter of the case so it should be fairly easy to spot. Check if oil is blowing onto the case from the tranny or other areas. Like someone else said, try to identify whether it is tranny,engine or primary fluid. Usually the tranny stays quite clean looking so unless you recently changed your fluids a relatively clean fluid leak is probably from the tranny.

 

I forgot to mention, my engine oil is going down proportional to the leak. When I get home I will check the level in the primary, if it's full, then thats bad news. Main seal leak, I guess. If the level is fine, then I guess it's one of the above mentioned possibilities.

 

You haven't mentioned it but, are ya regretting letting your buddy ride yer scoot? I don't need my friends to break my stuff...I do enough of that myself.
Good luck finding the leak and I hope it ain't too much work/money to fix it.

 

He's my best buddy and I ride his, actually he can ride a wheelie till he runs out of black top. But rest assured, he wont ride it like that again.

I have it on a lift now, what a pain in the a$$ because I have a lowering kit on it. It looks like it's dripping down from the back rear side of the primary case, right below the belt drive gear.

Any clues on what it can be? There is no oil anywhere on the engine itself, cylinders, pushrods, ect... No leaks from the primary case but, in reading the above post, the oil looks pretty clean however the oil was recently change before I bought it 2 months ago and I'm running 20-50 in all three holes so it probably taste the same, but I'll scrounge up an oil appetite tomorrow and taste it. [:'(]

I have the manual out right now and came in to post this reply.

I'll run it tomorrow cause it's late. How much of a deal is it to replace the trans seal, or how much will the stealership charge. I have a bike run up to Lake George in 3 weeks and I want to make sure I'm ready.

 

I have never tasted oil to determine from whence it came. Blea!
I must confess that I am unfamiliar with the newer transmissions so I may not be much help. You say you use the same oil in all three holes so your primary carries it's own oil supply (I set mine up that way...I don't know when the factory started doing that)? It gives me a moments pause when you say your engine oil goes down in proportion to the leak. It doesn't make sense that your engine oil goes down when the leak appears to be coming from the primary or transmission. Have you cleaned the area yet all around where the leak may be coming to determine its source?
I'm sure the HD service manual describes the tranny seal replacement (if you determine that is where the leak resides) so following your manual should get you through that okay. On my old bike (1979) there are two seals in that area and there may be that many or even more for your trans. so you'll probably want to replace 'em all while your at it. Perhaps some of the guys familiar with your year model will chime in with additional tips. There is probably a seal and bearing in the primary case where the transmission shaft goes through it that you'll probably want to replace. At least, do the seal while you have it apart. You will also need the oring where the primary case bolts to the engine and oring/seal/gasket (whatever it uses) where the starter motor bolts up to the primary as well as a gasket where the two primary halves (inner and outer) bolt together.
It is possible that the trans. pulley nut is loose and slugging it up will nail the leak but I ain't usually that lucky (Do ya feel lucky?).
I hope you get it fixed the first time. Pulling the primary is kind of a hassle to do more than once. For me, the first time is usually an adventure.

 

It could be from a lot of places,with the wind and the way oil will migrates.You may have to clean the bike then start fresh.