Panic Time - Where is the oil coming from??

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Greetings,

I'm in panic mode right now. I completed a valve check (swapped two exhaust shims) and now I am having a major oil leak out of the left side somewhere behind the valve cover. I assumed it was the valve cover so I removed and replaced the gasket and tried my best to carefully seat the new gasket but the leak remained on my second run.

Both times the engine ran fine. I've done valve checks and shim adjusts for 30 years now and always check/double-check after putting the cam covers back in place.

This isn't just an oil seep. Between both runs I figure I gave lost 1/4 quart of oil so it's blowing out of somewhere.

The oil looks fine in the sight glass. The plugs are clean. There was no smoke coming from the exhaust. I pulled the tank and got into the airbox, no issue there. I'm going to pull the airbox to see what might be going on below.

The one thing I am panicking about it the plug wires. I am always careful about getting the order but since the plug wires are now off, I've no idea if I had the wiring wrong. The engine ran fine so I can't see how plug wiring might be involved.

Edit: I just realized the plugs are on the same coil so it wouldn't matter if they were swapped.

Looking for some guidance from the forum on what I need to look at below the airbox. Thanks.
 
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dduelin

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Hard to think you pinched it twice but the usual suspect is trapping the rubber heat mat under the inside rear corner of the valve cover.

If the bike runs good the plug wires are fine.
 

ToddC

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Hard to think you pinched it twice but the usual suspect is trapping the rubber heat mat under the inside rear corner of the valve cover.

If the bike runs good the plug wires are fine.
:plus1:
 

Blrfl

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If it didn't leak before you touched something and it did afterward, you get three guesses where it is and the first two don't count. :D

It is really, really easy to get the heat mat pinched in the gasket. What I usually do to avoid that is slip a piece of thin cardboard between the mat and the cylinder head before installing the cover. The cover will nudge the cardboard and the mat along with it. Once the cover is installed, I pull out the cardboard and the mat flops anywhere but inside the valve cover.

Also make sure you torque the valve cover bolts down in the right order.

--Mark
 
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Igofar

Like Mark pointed out, using cardboard is a good way to protect the mat from getting pinched.
Another way is to simply remove the two bolts that hold the coils on and move them out of the way, this gives you a straight drop down on the cylinder head, and you can see all the way around it to verify nothing is pinched.
If your seeing oil run down the side of the engine, look and see if it is coming out of the drain holes directly beneath the exhaust pipe, and above the knock sensor switch. If this is the case, you have pinched the circular rubber gasket that goes around the spark plug well, and oil is leaking into the well (spark plug) and exiting out the hole.
As far as the bolts go, did you replace the oil seals with new ones when you checked your valves? You cannot (should not) try and re-use them, as they have very small ridges on them that help seal, and once used, they crush flat.
Make sure you DON'T over torque the bolts, I have seen several of these bolts bent from over tightening them.
Call me if you need any further help.
Igofar
 
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OK, I've calmed down a bit. I agree that is can really only be that pesky valve cover gasket / pinched mat. I am amazed over the amount of oil that leeches out and that alarmed me the most. I have had these valve covers off 5 times before with no issue but I guess there is always a time to be snake bit.

Thank you for your suggestion to use tagboard protector/guide Mark. I will fab one for my next attempt.

A few questions:

- I left the airbox in place once I realized that swapped plug wires are not a consequence. However I don't want to install the fuel tank yet either (at least until I make another attempt at the valve cover.) I assume there will be no problem running the engine without the upper fuel tank. I will reinstall the airbox cover first with the sensor.

- I did lightly "glue" the new gasket in place with Honda HT Bond but this doesn't seem like an appropriate application. Honda appears to use some sort of adhesive from the factory (instead of a gasket sealer goop.) Does anyone know what this adhesive is?

Plans this week (I am still a working stiff and Sunday is my ride day) is to sanity check my valve adjustment/cam cover installation. I don't suspect there is any issue by why not. Then I will make a third attempt at the valve cover.
 
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Does anyone know what this adhesive is?
Don't know what Honda used, but a good choice is Permatex Ultra Blue silicone gasket maker. Removes easily, when needed, and holds the gasket well in place during assembly.
 

STumped

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Hard to think you pinched it twice but the usual suspect is trapping the rubber heat mat under the inside rear corner of the valve cover.
+2

Yeah, I've boogered it up before and almost dropped the bike at a stoplight because my foot slipped on all the fresh oil spilling out...! I have been VERY careful ever since! ;)
 
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Question for those unfortunates.......:)

Is it always the left side? It seems harder to seat the cover on that side IMO.
 
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Igofar

Like Mark pointed out, using cardboard is a good way to protect the mat from getting pinched.
Another way is to simply remove the two bolts that hold the coils on and move them out of the way, this gives you a straight drop down on the cylinder head, and you can see all the way around it to verify nothing is pinched.
If your seeing oil run down the side of the engine, look and see if it is coming out of the drain holes directly beneath the exhaust pipe, and above the knock sensor switch. If this is the case, you have pinched the circular rubber gasket that goes around the spark plug well, and oil is leaking into the well (spark plug) and exiting out the hole.
As far as the bolts go, did you replace the oil seals with new ones when you checked your valves? You cannot (should not) try and re-use them, as they have very small ridges on them that help seal, and once used, they crush flat.
Make sure you DON'T over torque the bolts, I have seen several of these bolts bent from over tightening them.
Call me if you need any further help.
Igofar
Thanks for the tips. Yes, I did replace the cover bolt washers and yes, I am using a torque wrench that is set to the prescribed 10 nm torque.
 
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Another way is to simply remove the two bolts that hold the coils on and move them out of the way, this gives you a straight drop down on the cylinder head, and you can see all the way around it to verify nothing is pinched.
Igofar
This confuses me. The coil is not interfering as much as the main harness. I'm not clear how removing the coil mount would make a difference. This is a 2007, so maybe there is something different.
 

dduelin

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By removing the coil and the stud that serves to retain the middle cowl fairing piece you can move the wiring harness up and out of the way.
 
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This confuses me. The coil is not interfering as much as the main harness. I'm not clear how removing the coil mount would make a difference. This is a 2007, so maybe there is something different.
By removing the crank case breather hose and the left coil, you can then lift your entire wiring harness up over the stud on the frame and out of the way (move it to where the coil was).
There is no need to remove or loosen the stud.
The left side has more wires and stuff to get in the way.
 

jfheath

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Larry has probably already covered everything with you, but just in case - the rubber gasket doesn't need glue or sealant EXCEPT where the half moon shapes fit into the semicircular recess at the crankshaft ends. Without sealant in the corner where the half moon lump of rubber meets, oil will liberally coat your engine casing.

Its a pain, but any existing sealant needs to be cleaned off the gasket. Its difficult to see - it will be a very thin layer in the grooves.

Check that the seal around the spark plug hole is in place too.

Double check all of the valve clearances with a cold engine. It is possible that when replacing the crankshaft for the final time, that the cam chain can be tight against the sprocket. As the rear end is clamped down, the sprocket is brought into line and pulls against the tight side of the cam chain -resulting in the rear end not seating correctly. I cant remember the exact circumstances, but it had something to do with how i had positioned the sprocket in relation to the tight side of the chain. I'll see if i can find out what i did. Link. However, If this isn't noticed, the clearances that you set will be all wrong. It happened to me the second time i did the valve clearances and i could tell from how it felt on the previous occasion that it wasn't right. Maybe, the incorrectly seated shaft may prevent the cover from sealing correctly?

Final thought - when replacing the cam shaft, did you check the timing marks against the marks on the end of the crankshaft ? Or did you mark the timing chain and the sprockets to indicate where they were positioned before you started, so that you could put them back in the same place ?
If you marked the chain and sprockets, it may be that the chain has slipped round a tooth or two on the sprocket at the end of the crankshaft deep down in the engine, which would put the valve timing out.
 
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Blrfl

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- I did lightly "glue" the new gasket in place with Honda HT Bond but this doesn't seem like an appropriate application.
The gasket is self-sealing everywhere except the half-moons at the front, which are the only place you should be applying sealant. (FWIW, I use a light coating of Permatex 85409 for that.) You may find things a bit of an oogy mess when you remove the cover.

Depending on where you put the sealant and how much, you may have displaced the gasket enough for oil to escape. There's quite a bit of it flying around under the cover while the engine's running.

--Mark
 
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The gasket is self-sealing everywhere except the half-moons at the front, which are the only place you should be applying sealant. (FWIW, I use a light coating of Permatex 85409 for that.) You may find things a bit of an oogy mess when you remove the cover.

Depending on where you put the sealant and how much, you may have displaced the gasket enough for oil to escape. There's quite a bit of it flying around under the cover while the engine's running.

--Mark
I think there is some confusion. I did not apply any on the mating surfaces. I only applied a small dab here and there on the backside of the gasket to fix the gasket in place. Honda obviously did this from the factory with some sort of adhesive glue, not a gasket sealant. I abhor the use of gasket sealer in any gasket application for the obvious reasons (it's not needed and can possibly ooze into the engine.)
 

jfheath

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I did not apply any on the mating surfaces.
As long as you realise that sealant it is most definitely needed around the half moons - quote section 8 of the shop manual "Apply sealant to the cylinder head semi-circular cut-outs as shown", with a diagram that shows sealant around the entire semi circle.

As I said - if it isn't sealed, oil will get out at that point and coat the front or rear of the engine casing. I know because I couldn't be bothered to do my own shims last time and 'trusted' it to the dealer - who didn't seal it. It was a right mess.
 
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