Oil Seepage Around Filler Cap

[Stuart Bliwas]

Last weekend I intended to take my 04 1150RT on a trip of about 700 miles. In preparation I checked the oil and added about a half quart. The bike has about 9000 miles on it and uses about a quart every 2000 miles. On Saturday when I started out the temperature was down around 33F. It remained in the 30s until the afternoon and never rose above the 40s. At the end of the day I noticed oil seepage around the filler cap. On Sunday when we started the temperature was again in the 30s. After several hours of riding I noticed additional oil around the filler cap.

This has never happened before however, this was the coldest I have ever taken the bike out. Has anyone also experienced this problem and if so do you know what is causing it. Could it have any relationship to the outside temperature.

[W. Mazelin]

I don't know how oil could seep from the filler cap; is it possible that when you filled it, a little was spilled and you noticed it later? I have ridden my GS in similar temps, and never seen anything like that. The GS has over 51k milies on it now.

[Dr Klawn]

You probably need new O-rings. There are (2) - 1 on the cap itself and 1 under the plastic piece on the valve cover. Be careful removing and reinserting the plastic piece! That should take care of any leaking.

[DavidEBSmith]

Oil absolutely can seep from the filler cap. Typically it happens at higher mileage, when the o-ring on the filler cap or or the o-ring under the filler insert ages, hardens and starts to leak. There's enough air pressure inside the engine to force oil out through a leak o-ring. And then when you ride, it blows oil all over the side of the bike and your left leg. Ask anybody who's seen my Aerostich.

 

Could it be cold-weather related? Certainly o-rings can stiffen up and fail to seal properly in the cold, as we learned from the space shuttle. If one of the filler o-rings was sealing marginally, cold weather probably wouldn't help it.

 

Best thing you can do is clean off all the oil and keep an eye on it. If there's a leak, you'll see oil again. You'll have no idea where it comes from, because if gets blown around from the airflow over the heads. The filler cap o-ring is easy and cheap to fix, the filler insert o-ring somewhat less easy. You can replace the cap o-ring first and see if that solves the problem. If not, replace the insert o-ring (and consider replacing the whole assembly and cap so you have all new parts - it's pretty cheap).

 

I had a chronic filler insert leak until I replaced the stock o-ring with a Viton o-ring. Viton holds up better to high temperatures and is more resistant to gasoline. I don't remember the o-ring size off hand, but I have a lifetime supply of them in the garage (a bag of 10 was about $8 from McMaster-Carr).

[2wheeler]

What David said. I first noticed it about 15000 miles ago the morning after a long ride. The left saddlebag was covered as was my wifes suit from the knee down. I replaced both rings and it stopped. Now it's doing it again at 38k miles. It may be time to find the viton rings.

[DavidEBSmith]

For the insert o-ring, look here.

 

It's a 214 o-ring. McMaster-Carr part number 9464K35, $9.89 for a pack of 25, or for the Mil-Spec version, part number 1201T62, $8.29 for a pack of 10

 

The cap o-ring is a different size, I'll have to measure one.

[raysuf]

My 04 RT leaked from the day I picked it up from the dealer. I eventually got the leak proof Moto Tech cap. It doesn't leak any more. It was a pricey fix but worth it not to deal with the o-ring issue.

 

Ray

[Uggles]

Sure you aint just overfilled it?? This exact same thing occurred when the dealer overfilled mine last service. Check the level again

[TR RT]

My 04 RT also leaks. It has 6000 mles now and it is not overfilled with oil. I have ever-present oil streaks on the left cylinder head.

 

I worry that if oil can get out, water can get in. Is that reasonable or possible? Water sits fairly constantly in the filler well around the cap.

[BobFV1]

Last weekend I intended to take my 04 1150RT on a trip of about 700 miles. In preparation I checked the oil and added about a half quart.

 

Sure you didn't overfill it? Was the bike hot when you checked the oil? Otherwise you would have had a false reading.

 

Regardless, the stock plastic filler cap and plastic sleeve are pretty worthless. I replaced them with the Moto-Techniques setup and have had no leakage since.

[flatbutt]

Anybody else think 1 quart every 2000 miles is a little high?

[BobFV1]

It's more than mine burns but from what I've heard it is not that unusual.

[TVdawg]

How much oil the bike uses usually depends on the mileage. My RT used quite a bit of oil unitl 24K. Now it doesn't use enough to worry about between changes.

[Tom P]

Just in case...something I thought everyone knew except for me.

 

At our last tech daze Bruce noticed oil seepage around the filler cap on my bike and that my filler cap was not put on correctly. Never knew it was aerodynamic and some oil would seep out (as it had started doing)if it was not put on with the higher fin side facing the back of the bike.

 

No more seepage

[Blue Beemer Dude]

Anybody else think 1 quart every 2000 miles is a little high?

 

Nah, I'd be happy if that was all that mine burned. Currently at 11K miles, it burns it, leaks it (from the filler cap) and who knows what else...

 

I think weebles sneak into my garage at night and play mischevious little games, like siphoning out my oil, letting some air out of the tires, etc. I need to set some traps. Little bastards!

 

Michael