Hi,

94 FXSTC

My primary has a leak, either the drain plug or the seal right behind where the plug is-(where is meets the inner primary). Hard to tell because the plug is the lowest point and whatever leaks out migrates there. I had a little dampness there this fall but it seemed to be comming from the derby cover and running down. Changed the primary oil, used RTV on the derby cover and plug and all seemed well-Dry-but the bike has been sitting for the last month-(leaking petcock and bad weather). It was dry when I started it today but after a couple minutes warmup there was some on the ground. Wiped it all dry and went for a spin, it was just a little damp and has not leaked a drop after sitting for a few hours. Seems to only leak when running. It's not serious but I hate leaks.

Where does the primary vent?
I want to make sure it is open/clear.

Anyone ever had their plug leak?
I coated the threads with RTV when I last changed the oil.

It's been sitting for 4 hours and I just checked..totally dry so it only leaks when running...Thoughts??

Thanks
Doug

 

Never had the plug leak. Check your manual and look for seals/gaskets that may be the problem while oil is flinging inside.

 

Mine leaks... leaks slowly, but it leaks. Yeah, I don't like leaks either. My front cylinder base also weeps a tiny bit, but it's not bad enough to tear the engine apart to fix.

I had my outer primary cover off recently to install a new starter. It was leaking before I took it off, and it still does. I checked the gasket surfaces on both the inner and outer primary cases for any nicks or burrs when I had it cracked open, but didn't find any. When I put it back on, I used a new H-D gasket and a new drain plug with the white coating on the threads. I checked the torque on the primary bolts and on the drain plug.

Oddly, Bertha's primary doesn't seem to leak until after sitting for a week or so. Maybe I just need to ride her more... she seems to get all snippy when I don't pay enough attention to her!

Don't know about the primary venting... I don't remember seeing a vent hole when I had my primary open, but maybe there is one.

 

The primary vents past the clutch push rod extension and thru the transmission mainshaft, out the transmission housing vent hose.

Whether you use primary fluid, ATF or whatever, it's hard to spot a leak source because it doesn't get dirty so quick as engine oil.

Since it only seems to leak when running, you need to put it on the side stand and lay down on the ground from the right side of the bike with a flashlight and look up under it directly in line with the front drive pulley, on the backside of the inner primary. If it's leaking there you may not see fluid, but will see a "clean" streak where it has been running straight down... (if it's leaking from the inner primary seal).

 

The primary drain plug is usually coated with some liquid teflon thread sealant. And as you already know the derby cover is a big o-ring. I've never had a leak off the derby cover. I've never had to replace the 0-ring, or put any sort of sealer on the thread of the cover screws. And this is with either the OEM cover or the 'Live to Ride' cover.

Are you certain that it's primary fluid? I ask this because the EVO's have a history of the main drive pulley nut loosening up, and the pulley will move on the shaft. The pulley is what holds the output shaft seal in place. Once this happens the transmission will leak fluid out the splines and onto the inner primary. Then it will drip down the outer primary and onto the floor. Giving the impression that the outer or the drain plug is leaking. This is exactly what happened on my 1993 FLHS, until it loosened up and hit the inner primary on a rainy Saturday morning outside of Chambersburg, PA in 1995.

The MoCo developed an 'upgrade' to the nut/locking plate design in 1994, but it is merely a slightly heavier duty version of the older part. I had that part installed when my OEM one failed. It loosened up again in 2002 in Daytona Beach, FL. But this time I new EXACTLY what it was, and it was back in for repair before it hit the inner primary.

It's about a 3-4 hour job at the dealerships, because everything on the right side of the bike needs to be removed to get at the drive pulley. Then it all has to be re-assembled and re-sealed. Not a job you want to do on the side of the road, but one you can most likely do in your garage. Regular hand tools will work, however, an air impact will make loosening the 'big nut' much easier. I would also highly recommend that you install the MUCH BETTER designed lockplate/nut from JIMS.

 

The problem I having right now is the HD seals are no good, they leak from new. Both my wife's 85 FXEF and my 01 FXDXT both had transmission/inner primary leaks.

Both were brought to HD for repair and they both cost in the $500 range each and they both started leaking again within a couple hundred miles. Brought the FXEF back in and they "repaired" it again, again started leaking in a couple hundred miles.

Now put newspaper under them after shut down, wait a day, wipe down, throw newspaper away. Just to keep garage floor clean.

I believe the HD seals are either to hard, not right size. Since they are manufactured in China the conversion from inches to mm causes a slight discrepency and allows leaks.

just my .02

 

I have to disagree on the quality of the OEM seals, I have never had a problem with the OEM parts, and I have never seen one of these seals that was made in China.

Doug: first make sure that the transmission is not overfilled, also make sure the transmission vent hose is not blocked or kinked.

If those are ok, you will have to decide how bad you hate the leak.

If you decide to remove the inner primary, I suggest that you replace all the seals and the pulley spacer while you are in there. Also make sure you have the upgraded pulley/spacer/nut/lock that HACKD described.

 

I dont buy HD anything, cept scoots. I replace all my gaskets with James whenever
I can. Used them on both of my evo base gaskets and never had a problem. Tenn.

 

Thanks Guys,

I put a good light on the situation and Hackd nailed it, the area where the trans meets the inner primary is damp but it does not seem to leak when sitting. The trans is not overfull, I have not checked the vent yet but I'm never that lucky..LOL

If that nut on the pully came loose I guess it's not a good idea to ignor the leak and just drive it, and since I don't know if it's just a bad seal or the nut is loose I need to fix it...Correct?

I looked through the manual last night, I've never been past the outer primary and there seems to be some special tools needed. The PO didn't ride it much and it only has 25K on it but I also want to replace all the seals in there(and anything else), Does anyone have a list of parts I'll need and what special tools do I need-(& which ones can I do without). Any areas of caution I should be aware of..ie: (do that and this bad thing will happen).

I should be able to handle this, my garage is unheated so I want to gather everything I'll need so that when I get a warmer weekend I can knock it out.

Thanks,
Doug

 

Not you're making me wonder about that on my bike... Since mine is a '95, I would expect that I have the "improved" version, but it sounds like it isn't really much of an improvement. After having just bought over a grand in parts, I really don't want to go in there just yet...

It's freezing down here, too. I installed a Twin Tec single-fire ignition yesterday with my electric oil heater going full blast and I still nearly froze. If this cold keeps up, I will just deal with the bike after it warms up a bit!