R11RT Oil leak question

[VinnyR11]

I have an oil leak that I can't figure out. My R11RT, (~45k miles) drips about 10-12 drops of oil at start up. It drips pretty fast, but stops pretty quickly. As far as I can tell, the first few seconds of start up is the only time it looses any oil. The bike burns and looses virtually no oil over thousands of miles. Between oil changes I typically add only about 4oz total, and there are no noticable remnants of oil loss on the bike, my riding suit, or drivechain even after a long ride. I keep the oil level at the midway point on the spyglass when warm after allowing it to settle, so I don't think it's an overfill problem.

I cleaned off the engine as best I could, and it appears that the oil is weeping from a large nut that is on the top of the left jug close to the center of the bike. It may be dripping from a higher point, but I couldn't tell. I can't understand why it only does this for a short time, and not when on the road. I thought it may be a poor seal that "fixes" after heat expansion, but the bike will do this at start up even when warm.

Any ideas?

[Jim Moore]

Sounds like it may be coming from your left side cam chain tensioner. The cam chain tensioner is pressurized by engine oil, so when you first start, it is not pressurized. Lots of people have a cam chain rattle on start up that goes away after a few seconds. May your leak is stopping after your tensioner is pressurized. Can you get a pic of the nut?

[VinnyR11]

Thanks for the info Jim. I don't have a pic and I put the bodywork back. Since the oil loss is so small I figured I'll ride until I can get a handle on what's wrong. I should have taken a pic beforehand.....duh. Anywho's, hopefully this will help. The bolt is inbound of the cylinder head (towards the center of the bike). It is vertical (screwed downward) and almost exactly in line with the oil cap. It looks like about a half inch /12mm head. It's the only vertical bolt I noticed in that area.

[Ken H.]

Yeah, that's the cam tensioner. It's unusual for them to leak, but sounds like you need a new seal. Part #12 in this diagram - Cam Chain Diagram

[VinnyR11]

That definitely sounds like the deal, and luckily an easy fix.

 

Thanks A LOT guys!

[Clive Liddell]

I have not R&R my cam chain tensioner but If you check the position you will see that it ends up quite a job to just renew the gasket.

 

I would firstly try and retorque it in position and then if it still leaks go the replacement route.