Primary Oil Leak

[SpringerSteve98]

I get a leak coming out of my overflow into my air breather when i run over 2k miles without an oil filter change. Usually changing my oil filter will cure the problem. I think what happens here is the oil filter gets clogged a bit, then creates a higher oil pressure and causes oil to run out my overflow (which convieniently runs into my air filter). But in response to your question - Its possible putting an air filter with higher flow might help the overflow a little. The only reason i say this is because where the oil vent ends up is actually inside your air filter. I'm assuming theres a bit of vacume in there (sucking on the end of the overflow) while the bike is running. So logically, having a higher flow air filter would decrease the amount of vacume pressure inside the air filter assembly (where your overflow ends up). I don't know thats its going to make that much of a difference, but mabye some. When mine starts puking oil thru the overflow i put a fresh oil filter and fresh oil in it... It helps.

I have a leak coming from that general area also behind the inner primary ('01 FLHRC). Really only noticable after riding and the oil has sprayed over my rear pipe and the ol' lady's pants leg. When it sits afterward it only drops a spot the size of a quarter.

OK, looking back over your question... Your primary is on the left side of your engine. Usually the pipes are on the right side? This leads me to believe its coming from your air breather instead of your primary.

 

[Eyesman]

I thought that too at first, but find no oil on or in the air cleaner. However, the furthest rear of the inner primary to the bottom is always wet. My thoughts are the air flowing over the right side of the engine creates a vacuum like a siphon feed spray gun, and the oil is only across the rear downtube. The drip is right under the lowest primary cover bolt. The spray isn't heavy, more like a mist it seems. Just enough to leave a residue.

Will have to pay closer attention once I start riding. Would have had her out already the past couple days, but the original battery finally gave up the ghost. Picking up a new one Thursday while the rain is washing the salt and sand off the roads. Been a long winter. Just enough nice weather lately to tease us. Will be over soon.

Thanks for the reply. All ideas are welcome so I'll have places to look.

 

[Chopper]

In 04 harley started using a improved seal in the primary and if you have never had it changed it's a good possibility that's the leak, it's common on the older bikes, if you wash off the underside of the primary and take it for a short ride and check it and the bottom of the primary is wet, then it would be a good bet. Using a dye will tell you for sure.
View attachment 5925

 

[bassman61]

Yeah, talk about a frustrating situation....I have been dealing with a very similar problem for the past month or so. I've been getting small leak spots on the ground, right underneath the bottom of the primary. I have had a couple of friends check this out for me, and they both seem to think it is indeed the fact I filled the tranny too full. I checked the dipstick and sure enough, it is ABOVE the FULL mark. I have also heard it will eventually spit out the excess through the breather tube. Well, all of that is fine and dandy, the only thing that I find confusing is that I hear that tranny fluid is usually a light color, even after putting some miles on the bike after the fluid changes. For the record, the oil leaks I'm seeing are usually a dark brownish-black color, which makes me think engine oil. I check my oil level, it is OK. I use Amsoil Severe Gear oil in the tranny, and Amsoil 20-50 in the engine/primary.

Any words of wisdom? I don't like to see leaks!!

ED

 

[NEWHD74FAN]

As with any leaks, it will find it's way to the lowest point on bike, and spread by airflow up and around the bike. Best way is to throughly flush, clean and dry your bike completely, especially in low lying areas. Once completely dry, wipe down one more time with paper towels as much as possible the entire underside up to and including under the seat. Wait and hour or so, and use a wad of toilet paper. It will stick where ever there is oil, allowing you to identify and fix properly. JMO

 

[mmward45]

Hello have owned honda in the past well i have a 92 heritage softail with 7700 miles on it and know i am trying to find a oil leak behind the primary between it and the tranny, can i take the harley oil out and put hy tach gear lube in it. i have used it in rearends of trucks and leaks would stop. its purpose is to stick to the gear to prevent dry gears and no leaks

 

[fin_676]

Hello have owned honda in the past well i have a 92 heritage softail with 7700 miles on it and know i am trying to find a oil leak behind the primary between it and the tranny, can i take the harley oil out and put hy tach gear lube in it. i have used it in rearends of trucks and leaks would stop. its purpose is to stick to the gear to prevent dry gears and no leaks

My thoughts on this one would be to to replace the seal thats leaking and use the correct lube for the gearbox
if the leak is dripping down from the primary and it is gearbox lube i would suspect the mainshaft oil seal, the mainshaft carries the drive from the clutch into the gearbox and seal runs on on the gearbox end of a wee bit of exposed shaft and can get dirt on that wee bit of shaft that will then cause the seal to fail

Brian

 

[Jack Klarich]

My thoughts on this one would be to to replace the seal thats leaking and use the correct lube for the gearbox
if the leak is dripping down from the primary and it is gearbox lube i would suspect the mainshaft oil seal, the mainshaft carries the drive from the clutch into the gearbox and seal runs on on the gearbox end of a wee bit of exposed shaft and can get dirt on that wee bit of shaft that will then cause the seal to fail

Brian

Brian, I love the way you write would love to hear your accent

 

[fin_676]

Brian, I love the way you write would love to hear your accent

My accent is a wee bit mixed up as im from north east scotland and was brought up speaking doric had to learn english at school but once in the british army i had to change the way i spoke so that people from the rest of the uk could understand me
still got a scottish accent but not a real banffshire accent any more or i would only be understood in banffshire

Brian

 

[larryb]

Having an issue with a 95 dyna, replaced quad seal, oil seal, race/spacer and still tranny fluid is seeping down the shaft, any ideas?