Oil leak

[Aram]

Hi all,

 

My '04 1140RT developed a small oil leak. I just noticed a coating of oil on my left valve cover. I see oil on and around the oil fill plug, down the valve cover side, and some toward the back (not too surprisingly). I'm down from halfway up the sight glass to maybe one quarter, over about 1500 miles -- nothing major.

 

I've only had the bike for a little over a year, so I'm not very familiar with its idiosyncrasies. Where would you look? It never did this before, which I suppose suggests the fill plug (only part I took off at last oil change). Valve cover gaskets? Anything else I should look at, or would you just put a new o-ring on the fill plug and give it a go?

 

Thanks,

Aram

 

 

 

[szurszewski]

Probably the filler - pretty common. There is a plastic insert with an o-ring that lives in the valve cover, and then there is the plug with its o-ring. Some people have luck taking all that apart and cleaning them up, some have better luck replacing the o-rings and the insert itself. Some people do all that and still have some weeping. Yours looks like more than just a weep though.

 

If you can't tell if it's coming from the filler, the best thing to do would be to get everything really clean and then keep a close eye on it. Do that and you will probably be able to see pretty easily where the oil is coming from.

[Aram]

Thank you. Good advice, much appreciated.

 

Aram

[SAS]

Aram,

 

You can also use talcum powder to find the leak. Clean it up and put the talc on it and see if you can sea a trail.

[Jim Moore]

Hey, I just went through this and I happen to have a few spares in the garage. Send a $5 donation to your favorite charity and I'll get one in the mail to you.

[dirtrider]

Morning Aram

 

First place to look is at your L/H fork seal area, in some cases the fork seal will leak then the oil can blow back on the valve cover while riding.

 

Your problem does look (in the pictures anyhow) like one of the filler cap "O" rings is leaking. (see blue arrows in picture below)

 

If you have just switched over to synthetic motor oil, or to a different brand of motor oil, then some synthetics have very little seal conditioner in them so the "O" ring can shrink slightly.

 

[Aram]

Thanks everyone! Jim, check your PMs.

 

Aram

[Bob Boro]

How is the lower O-ring replaced? Does the plastic part pull out, unscrew, or just how is it removed to replace the lower O-ring? Thanks!

[Jim Moore]

You pry it out, gently.

[Aram]

Just want to say thanks, all. I replaced the plastic collar, its o-ring, and for cheap insurance the o-ring on the plug. Just a couple of hundred miles on it, but the cover appears to be dry now.

 

Thanks!

 

Aram

[Bob_1978]

I also have an '04 1150RT and had chronic leaks on the crankshaft seal. After seeing some stories / opinions that synthetic oil may be the culprit, I switched to the oil that the bike was designed for - Spectro 4 20W/50, and the leak went away.

[dirtrider]

Evening Bob

 

It's usually not the synthetic oil part itself, it's more the design criteria for synthetic oil usage.

 

Most modern synthetic oil is designed/developed with high fuel economy in mind. That means a lot of modern synthetic oils contain low amounts of seal conditioner. (less seal drag = more MPG)

 

A lot of older version dyno oils (especially in the higher viscosity range) have more seal conditioner content.

 

Same holds for gear oil-- I have seen a number of older 1100/1150RT final drive pinion seal seeps stop seeping with a switch back to old spec dyno gear oil.

[Bob_1978]

Thank you Sir, for the additional info -- much appreciated. I won't go back to full synthetic but don't mind spending an additional $1/quart for Spectro Golden Semi-Synthetic if the benefits are there. Would that increase the risk of oil leakage? Is it worth any risk at all if I'm changing at 3,000 miles anyway?

 

I'd appreciate your advice.

[Bob Boro]

Aram: Was it difficult to pry out the plastic collar? Any tips you can give me? I may be doing the same thing soon.

[Aram]

Aram: Was it difficult to pry out the plastic collar? Any tips you can give me? I may be doing the same thing soon.

 

Sorry for the delay. I just saw this.

 

No difficulties at all. it's trivial. You're actually levering the plastic to pop out the o-ring, which is what lodges it in place. I used a small screwdriver and removed it quickly, easily, and without a scary moment.

 

Aram

[rich t]

I just changed my O-rings this week. I was surprised, that it was actually tougher to get the insert back in, than it was to pop it out. I used a long wide flat bladed screwdriver to pop the insert out (carefully). Key to getting it back in is to make sure you have the insert's properly indexed and the insert presses straight in. If it's not lined up straight, it isn't going in.

[JamesW]

Went over to the local Tru-Value hardware the other day with my 11 year old "O" rings and selected a couple that looked very close in size. They worked great. Probably payed a lot less than at the beemer store.