Thin film of oil on trans cover?

NewRider

Member
Nov 24, 2015
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I just recently noticed a thin film on the trans cover. I do not see any leaks under the bike when it sits. Any ideas.

approx 7500 miles on bike, I first noticed this about 500 miles ago.




oil Trans Cover.jpg
 
Last edited:
You mean the cover on the top of the trans? Without seeing it, or knowing anything about your bike it is very hard to guess, but...
1. Rear cylider head gasket.
2. Rear cylider valve guide loose, oil leaking into exhaust port, and some of that escaping past exhaust gasket.
3. If you have changed your air cleaner housing and no longer run the crank case venting into the air cleaner; to where did you run the vent hose? Is it in front of and above the trans cover?

These are WAGs, clearly, but if I had an unexplained oil film on the top trans cover then I'd check these areas.
 
If its in warranty, let the dealer worry with it.

Well, I may need to do that, but I hoped someone could give me a few things to check, and it would be something simple and a quick fix.

The oil is coming through the bottom of the filter.

I do have an S&S filter. It has been on for over 6000 miles and this just started to happen. I didn't want to have the bike at the dealer and hear, well you changed the exhustfilter and altred the stock map so there is really nothing we can do for a non OEM/stock setup.

BUT you are correct, Only one way to find out.
 
UPDATE:

The oil was coming from behind the air cleaner. I took it to the dealer, they said a small amount was normal, nothing to worry about.????
Not sure if this is correct, but I cleaned everything off, and after about 750 miles, nothing so far.
 
In case they didn't explain it to you; the oil is coming out of the head breathers that vent into your air cleaner. They vent excess crank case preassure. Getting some oil mist blow-by through these vents is not unusual, especially if you run your engine at high RPM. I guess you had a few drops build up and weap out of your air cleaner then splatter onto your trans case? If it doesn't happen again then you probably have nothing to worry about. However, I would check for this condition by pulling off the air cleaner after a ride to ensure there is not a bunch of oil residue built up. It might not always leak out of the air filter. Just until you're sure the excessive blow-by has stopped happening. If you keep getting a lot of oil venting then it may mean there is something causing excessive crank case pressure.
 
Oil blow-by is common and doesn't necessarily indicate anything wrong. You can run slightly less oil or run to external catch can. I went the catch can route.


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Oil blow-by is common and doesn't necessarily indicate anything wrong. You can run slightly less oil or run to external catch can. I went the catch can route.

Hey brothers help me out, I'm getting a lot of oil blow-by every time I ride. I just started a new tune on FP3 to see if that's the problem, but what is an external catch can? How is it installed and used?

Thank you!
 
Factory setup is to drop the breather tube right at the intake so blow-by is sucked into the intake, but when there's a fair amount of blow-by it doesn't all get sucked in (as you've experienced). You can run with less oil, for example, to reduce blow-by, but I don't like sucking all that into my intake so I went with an external catch can. You route the breather tube to a can that collects the oil vapor and then exhausts to the atmosphere. I'll see if I have any pics to post.


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Thanks for the reply Happy G but I replaced my air filter with Screamin Eagle heavy breather and the "breather tube" is removed with that installation.
 
One solution I have seen for this in lieu of a catch can was to take a panty liner, cut to fit and two way tape it to the inside bottom of your air cleaner housing, if your air cleaner housing allows for this.

Replace every XXXX miles when the pad looks bad.

OK, I am ready for the abuse.

Ken
 
One solution I have seen for this in lieu of a catch can was to take a panty liner, cut to fit and two way tape it to the inside bottom of your air cleaner housing, if your air cleaner housing allows for this.

Replace every XXXX miles when the pad looks bad.

OK, I am ready for the abuse.

Ken

um well... that's one way to do it:eek:.. do you take one week a month to not ride her as well?..or you may just have to put on some protection before you mount her next time.

Perhaps some may just use the "pill" bottle to catch the excess.. other just use some form of diaphragm..:rolleyes:

ok i'll stop... couldn't resist :)
have a great day boys!
 
Sooooo advice from a so called machanic at the dealership, "loose the tuner" after I rolled my eyes he said to remove my intake a check for a tight fit and the o rings around the mounts, he confirmed there is no breather tube, I see now where the oil comes in, from two small holes on the plate. I'm going to go back to stock tune to see if it helps and YES I'm going to put a mini pad in her until then. I've done it on an old sportster LOLIMG_6039.jpgIMG_6039.jpg
 


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