I will give you a history so that maybe you can give me some pointers about where to begin…


Dealer did the 1.000 mile service on my new Night Train in January, I think it was.
I rode the bike about 300 miles after the service, bringing the total miles to something like 1500 or so.
I left for Daytona, visually inspecting the bike but I didn’t really touch the bike.
I rode in a variety of conditions, and spent about 5 hours on I-95 at about 75-80 mph on the way to Daytona.
I stopped in Brunswick, GA to fill up for the final run into Daytona.
I stopped at the Florida welcome center about 60 miles later to call my friend and tell him that I would be arriving in Daytona that night, after riding straight through. While at the welcome center I smelled burnt oil thinking it was coming from the car next to my bike. When the car backed out his lights hit the right side of my bike which I then noticed was glistening with some kind of moisture. After taking a closer look, I noticed that the oil filler cap had popped up and that oil had been streaming down the oil tank, on to my pipes, rear saddle bags, rear tire, and rear brake caliper and pads.
For the first time, I pulled the oil filler cap and checked the oil level. It was slightly above the oil fill line. I rode another 15 miles, stopped and bought some 20-50W oil, and brought the oil back up to the proper level with about ½ quart of oil.
Since I was wearing leathers and loaded down with luggage, I thought there was a possibility that by dragging my boot just over the seat to get off the bike that I had somehow kicked the oil filler cap loose.
When arriving in Daytona, I took the filler cap off, cleaned the rubber seal, cleaned the filler tube, and put the cap back in making sure it was secure and that the oil level was correct.
I spent some time hunting down some Harley execs while I was there. They were unaware of any specific issue regarding the oil filler cap. An employee at the Daytona Harley shop, however, said that he had heard someone talking about this kind of problem.
I rode the bike for 8 days around Daytona at varying speeds.
I rode back to Roanoke, stopping in Charlotte, NC this time, on business. I rode straight through to Charlotte. When I make my last stop for gas just south of Charlotte, I noted that the cap had popped up again. I thought, AHAH, I have kicked the cap loose again, but I couldn’t imagine that I could hit it with such a precise strike that it would pull the cap out of the tank. I pressed the cap back in and rode to Roanoke the next evening without event.
I rode the bike to the RVHOG meeting Tuesday night.
Tonight, I rode about 5 minutes from my house. I went in to a restaurant for about 1-1/2 hours. When I came out, I noted that the cap had popped off and that there was oil down the side of my bike again. The weather has been reasonably warm on the way back and since I returned and I have worn my chaps and was able to get off the bike with no threat of hitting the cap. I have deduced, therefore, that it is not me that is making the cap pop off.


This is driving me crazy. I haven’t found, on first look, anything on the internet about this kind of problem. There are two crankcase vent tubes, one from each cylinder, that hook up to the EFI system. There is a vent tube from the tranny, too. I seriously doubt that all three of these could be plugged in such a way that the cap would be popping off from crankcase pressure. I would hate to think that I need to continually check to see that the oil filler cap is seated properly… and that something like vibration is causing it to work it’s way loose, but that is all that I can come up with. I am thinking about getting a flat faced oil ring to put over the rubber stopper to tighten up the filler cap.



Do you have any ideas?



Thanks.



Craig

 

Never heard of it. Get your dealer to give you a new cap and try that. It sounds like some kind of pressure build up or the cap is not tight enough.