Valve cover leaking

[Mudduck]

I think my valve cover is leaking I smell a little burnt oil smell and it looks wet not much but something I want to fix. How hard of a job is it and I should probably adjust the valves while I’m in there. I there any extra parts other than the valve cover gasket? Thanks I’m looking to get a service manual before the job.

 

[ARKNT]

The NT valves are screw and locknut so easier than many. It does get a bit tight in there.
I would get the manual, it is good to have.
Also oil leaks can migrate so are sometimes difficult to identify the location. You may want to clean up the area and try to verify exactly where to leak is before digging in there.

Arknt

 

[Mudduck]

The NT valves are screw and locknut so easier than many. It does get a bit tight in there.
I would get the manual, it is good to have.
Also oil leaks can migrate so are sometimes difficult to identify the location. You may want to clean up the area and try to verify exactly where to leak is before digging in there.

Arknt

Yes I’m definitely going to get a service manual before I dig into the bike. The valves are why I buy Hondas over the bucket and shim type valves way to much for me to tackle. From what I see it does look like it’s coming from the top and working its way down. I can live with it for now until I’m ready to dig in. Thanks for the reply.

 

[DirtFlier]

For your sake, I hope the leak is coming from the cylinder head cover for the rear cylinder because the front cylinder head cover is much more difficult to access.

 

[harryhendo]

The tank is hinged, so you can pull it up from the front and rest it on a length of wood. Once that is done, it isn't too difficult to remove the valve covers. New gaskets are inexpensive. The torque on the bolts holding down the valve cover is very low, something like 15 nm, so it is easy to strip them when tightening them. An educated guess is that the previous owner tightened them down to the point where they stripped and came loose, causing seepage around the cover gasket.

 

[mikesim]

The tank is hinged, so you can pull it up from the front and rest it on a length of wood. Once that is done, it isn't too difficult to remove the valve covers. New gaskets are inexpensive. The torque on the bolts holding down the valve cover is very low, something like 15 nm, so it is easy to strip them when tightening them. An educated guess is that the previous owner tightened them down to the point where they stripped and came loose, causing seepage around the cover gasket.

I would sincerely hope that the bolts aren't stripped! The gasket is like a formed "o"-ring that fits in a machined channel. If you are not careful and don't hold your tongue just right when you put the valve cover on you can dislodge the gasket from the channel with the resultant oil leak. A good practice then is to fire up the engine and look for leaks BEFORE reassembling all the Tupperware. This is the voice of experience talking to you!

Mike

 

[junglejim]

The tank is hinged, so you can pull it up from the front and rest it on a length of wood. Once that is done, it isn't too difficult to remove the valve covers. New gaskets are inexpensive. The torque on the bolts holding down the valve cover is very low, something like 15 nm, so it is easy to strip them when tightening them. An educated guess is that the previous owner tightened them down to the point where they stripped and came loose, causing seepage around the cover gasket.

It has been a long time since I serviced my Nt (Sold it 6 years ago) but I seem to remember that the valve cover bolts screw into the cam block and the screws have a cut in them designed to break before they strip the. cam block. And YES they have a very low torque spec.

 

[DirtFlier]

I always use a small dental mirror and flashlight to check the edges of the formed gasket to make sure it's fully in place after the cover is reinstalled. The front edge for the front cover is always a suspect for the gasket being pushed out of place. The torque is so low (7 ft-lbs) I always use a short box wrench to tighten those screws.

JJ - the cover screws have a thick shoulder that bottoms nicely but I don't recall ever seeing a break notch?

 

[rc_heli_nut]

Tips on valve cover gaskets, these techniques worked for me:

1. Replace the 2 grommets too, they get compressed with age, replacing them ensures the cover is pulled down properly.

2. The gasket fits tightly in the groove in the cover it can be difficult to get it level. If you put some petroleum jelly in the groove of the cover using a epoxy brush, it's easier to install it level, and the petroleum jelly will melt away once the engines hot.

3. Put a dab of Permatex RTV grey or black, in the 2 corners of the gasket where the half-circle meets the straight run, this seals up the sharp edges at the 2 points on the cylinder head notch.

4. To avoid knocking the gasket out of place, rotate the crankshaft until the front exhaust valves are fully open. You can rotate the engine without removing the left crankcase cover plug, with the bike on the center stand, put the transmission in 5th gear, and bump the back wheel.

 

[DirtFlier]

#4 is especially important for the front cylinder!

Without the ex valves being open, it's a real struggle to get the cover onto the head and my guess is that you'd increase your chances of dislodging the formed gasket by 50%.

 

[junglejim]

JJ - the cover screws have a thick shoulder that bottoms nicely but I don't recall ever seeing a break notch?

Hmmm. Probably some other motorcycle with OHV and screw adjusters. I’ve had several. Can’t even remember how many. Bad memory.