Unpleasant Surprise

[RCinNC]

Last week I did a spark plug change. As I'm doing that, I find oil in three of the four spark plug wells. I wasn't super concerned at first; I usually put a bead of Belray waterprood grease around the coil stick to help seal the spark plug well from water intrusion, and I initially figured "well, I guess that grease must have broken down over time from heat".

About a day later I go out to the garage and I see a few drops of oil on the floor on the left side of the bike. A closer look revealed this:

What a drag. I have a new valve cover gasket on the way. I hope that's the problem, and there isn't another unpleasant surprise waiting in the wings....

 

[Paul466]

If you wrestle with the valve cover, you might as well check the valve clearance, don’t forget to glue that gasket to the cover, it’s so much easier to install

 

[RCinNC]

That's the only maintenance task in 10 years of ownership that I've always farmed out to a shop to do. I did buy the clutch cover gasket with that in mind.

 

[Paul466]

That's the only maintenance task in 10 years of ownership that I've always farmed out to a shop to do. I did buy the clutch cover gasket with that in mind.

Actually, i don’t think you need it, I’ve removed that cover multiple times and gasket is ok.

 

[RCinNC]

I always get one just in case the mechanic messes the old one up when he removes it. That way I won't have to wait two weeks for the shop to get another one and finish the job. I figure if they don't use it, I can always return it.

 

[Paul466]

I always get one just in case the mechanic messes the old one up when he removes it. That way I won't have to wait two weeks for the shop to get another one and finish the job. I figure if they don't use it, I can always return it.

The trick to removing that cover is to take your time with getting the harness out of the way as much as possible, there’s one way way it comes out, slightly turning it as pulling it out.

 

[RCinNC]

Yeah, I have a service manual and checked out the instructions for replacing the gasket. Sometimes I just get lazy and I want someone else to have to deal with the hassle.

 

[Paul466]

Yeah, I have a service manual and checked out the instructions for replacing the gasket. Sometimes I just get lazy and I want someone else to have to deal with the hassle.

I understand, but the positive to doing it yourself is knowing it’s done right , don’t be intimidated of valve check, it’s not hard especially if you have the manual, besides there’s an army of people on here willing to help with any information that You might need,

 

[RCinNC]

Lol, Paul, I'm not intimidated by maintenance....

It's just a task that I'm fine with subbing out to a mechanic. I trust the guys at my local shop to be able to handle it. They've done fine with it the last three times.

 

[whisperquiet]

I would check the valve cover bolts to ensure they are tight/snugged down before replacing the gasket. I left one finger tight several years ago, it leaked, and when re-tightened properly quit leaking.

 

[RCinNC]

Could be, though my last valve check was in Sept 2021, so if it had been loose when it was installed, I figure it would probably have leaked before now.

One screw up I may have caused was that, when the last valve check was done, I didn't replace the rubber mounts on the 6 valve cover bolts; I just had them reuse the old ones. That may have resulted in the valve cover bolts being overtightened, and it might have squished the valve cover gasket slightly out of position. It just took some time for the oil to work it's way past the weak spots. I'm going to tell the shop that I want the old gasket, because I want to see what the failure point was.

 

[holligl]

Make sure the breather hose hasn't come off.

Sent from my SM-S918U using Tapatalk

 

[RCinNC]

First thing I did after seeing the oil on the engine. It's still on the airbox (I have a worm drive clamp on it). Plus, with finding oil in the spark plug wells, I figure it's a good bet that the tube seals in the valve cover gasket are leaking.

 

[~TABASCO~]

Question :
Has your bike been ‘dry’ and normal for a while like ‘normal’? For months or years?

And just all of a sudden this oil has appeared?

If so that is not typically a good sign. You might want to take a flash light and see if anything has popped up and possibly cracked the valve cover.

On the other hand- if you have just very recently has some maintenance performed it’s probably just an unseated gasket. If the spark plug holes have oil, the 3 of the 4 round gaskets were not installed correctly.

Anyhow, please post a few photos & info on what you find so we can all learn.

Thank you

 

[RCinNC]

The bike has never had a leak before. But I guess everything is leak-free, right up until it isn't. The most recent maintenance I did was on 03/15/24, when I changed the spark plugs. That's when I found the oil in the first three spark plug wells (from left to right). It was a day or two after that, after I had ridden the bike, that I noticed the drops of oil on the garage floor. So the plug wells already had a leak when I changed the plugs, but the leak didn't appear in the valve cover area until shortly after that. Or at least, it wasn't leaking enough to be producing drops that fell on the floor until shortly after that.

The last time I was in the engine area was 07/14/22, when I changed the plugs the previous time. There's been other maintenance since 07/14/22, but none of it involved lifting the tank, removing the airbox, etc.

I've looked up in there with a flashlight, and as far as I can tell, there's no obvious crack where I can see. It's possible that I kinked the breather hose in some manner when I was changing the spark plugs, and the pressure increase might have forced oil out of an already weak spot in the gasket.

The leak appears to be coming from the front left side of the joint between the valve cover and the head. That's where the oil sheen is the most noticeable. It's not quite at the corner of the valve cover, maybe a few inches to the left of it. It looks the the oil that's on top the valve cover got sprayed up there while I was riding.

There's nothing in the performance of the engine that would make me think it was an internal issue, like a cracked head or something. I'll check the sight glass later today when I work on the bike and see what the oil looks like, but I haven't lost and coolant anywhere.

My plan is to remove the tank and airbox today and see if I messed up and somehow kinked the breather hose, and I'll be able to see more of the valve cover to check for any damage to it that isn't visible from outside. That'll give me a chance to clean it up a little and see if I can pinpoint the leak.

 

[holligl]

Perhaps the air box drain bulb got knocked off? I can't remember its exact placement.

 

[RCinNC]

The story continues....

I tore everything apart again today, and this is what it looked like (and possibly my thoughts on what's going on):

Here's the breather hose to airbox connection, and the airbox drain. Nothing looks amiss here.

Here's the breather tube to valve cover connection.

There were no kinks in the breather tube.

Here's the breather tube fitting with the breather tube detached.

This is the end of the breather tube that connects to the valve cover

Coil sticks 1 and 2.

Coil Stick 1, removed from the spark plug well.

Spark Plug Well 1. You can see the oil seeping past the tube seal.

Here's Coil Stick 1. You can see that the end is pretty soaked with oil.

Here's Coil Stick 2, in the same condition.

Here's Coil Stick 3, in the same condition.

Just like when I changed the spark plugs, spark plug wells 1, 2 and 3 had oil in them. Based on how high up the coil stick the oil appears, it looked to me like the oil was leaking down onto the coil sticks from about where the tube seals are located. I couldn't see clearly into spark plug wells 2 and 3 to be sure that the oil was actually coming from the tube seals, but the location of the oil on the coil sticks makes me think that the oil's coming from the same place as it is in Spark Plug Well 1.

I didn't pull Spark Plug 4; I didn't think there'd be any point. It was dry last time, and even if it was wet now, it doesn't really change anything.

I looked really closely at the valve cover from as many angles as I could see, and I couldn't see any damage anywhere on it. There's no damage anywhere on the cylinder head either, or the crankcase.

I didn't drain the oil, but I can see the oil through the sight glass, and it doesn't have that chocolate milk look that happens when a head gasket blows and coolant gets in the oil. There's no coolant loss that I can tell.

Here's what I think is happening:

I believe that the breather tube fits into a PCV valve on top the valve cover. The PCV valve, it it's like a car, is a one way valve that vents pressure inside the engine but doesn't allow anything to enter through the valve. If the valve is stuck in the closed position, then the pressure can't vent through the valve and has to go somewhere else. That might explain why three of the tube seals began to leak oil, and why a secondary leak may have later appeared on the left front part of the valve cover gasket; the internal pressure breached the tube seals first, and the continued extra pressure in the head eventually forced oil out the front also.

I looked on line at Rocky Mountain ATV, and I don't see the vent on top the valve cover listed as a separate part. Is that vent tube a PCV valve? And if it is, can it be replaced, or is it integrated into the valve cover and you have to replace the whole part? Is there any way to test a PCV valve while the valve cover is still in place?

I got my new valve cover gasket and rubber mounts today. I'll probably have it installed regardless, since the old one has already leaked.

I didn't want to run the bike again after I finished to look for a leak, because I don't want to to take a chance on fouling the plugs and have to take everything apart a third time so I can ride the bike to the shop.

So, anyone have an opinion on my theory, or a different theory of what's happening?

 

[WJBertrand]

There’s no PCV valve in that vent. It’s just a tube.

 

[RCinNC]

It figures. I beautiful damn theory, ruined by inconvenient facts.

 

[holligl]

Looks like bad/unseated gaskets to me. I've never replaced the rubber mounts on the cover bolts. I replaced the cover gaskets once, sealed to the cover.