Oil Drip, Timing Case Cover - 1987 K75S

[mieczkow]

I've got a small drip started and it is collecting right at the lower edge of the timing case cover where it meets the valve cover. Based on the "oil trail" it looks to be creeping along the lower edge of the timing case cover. The valve cover gasket was changed just a few years ago so I'm pretty sure it's not coming from there. Also the oil pump was redone a couple of years ago and it's not a drip that comes from the oil pump (I'm familiar with that one!).

I'm thinking I may have to pop off the timing case cover and re-seat it. I notice it has not gasket so I assume usual metal-on-metal sealants to be used. Is that correct? Also I notice that there is a shaft seal for the shaft coming into the space - while the cover is off should I go ahead and replace that seal? Is that a realtively straightforward job or does it get complicated?

Any advice is appreciated!!

[moondog]

I've got a small drip started and it is collecting right at the lower edge of the timing case cover where it meets the valve cover. Based on the "oil trail" it looks to be creeping along the lower edge of the timing case cover. The valve cover gasket was changed just a few years ago so I'm pretty sure it's not coming from there. Also the oil pump was redone a couple of years ago and it's not a drip that comes from the oil pump (I'm familiar with that one!).

I'm thinking I may have to pop off the timing case cover and re-seat it. I notice it has not gasket so I assume usual metal-on-metal sealants to be used. Is that correct? Also I notice that there is a shaft seal for the shaft coming into the space - while the cover is off should I go ahead and replace that seal? Is that a realtively straightforward job or does it get complicated?

Any advice is appreciated!!

There is no oil behind the timing cover.
What might be leaking is behind the timing chain cover. It could be the Hall Effect seal or something else. You need to pull the cover to find out what is leaking. Or it could be the oil pump and it is blowing up on to the timing chain cover. Investigate some more.

[98lee]

Also have a look at the oil pressure sender (under the boot on top of the oil pump). A leak there tends to travel with all the wind that hits it.


When you replaced the valve cover gasket, did you replace the rubber bushings on all 10 of the valve cover bolts? It is the resiliency of the rubber bushings NOT the tightness of the bolts (they are designed to bottom out) that provides the clamping force to the valve cover. If they are old and hard, they do not provide adequate clamping to the valve cover and its gasket, hence it leaks.

[98lee]

Just to clarify things, there are two timing covers.

There is the T shaped IGNITION timing cover on the crank cover side of the front of the motor. This cover bolts to the timing CHAIN cover. The ignition timing cover should have no oil behind it as there is an oil seal in the chain cover keeping oil from getting in. There is a gasket on the ignition timing cover, but that is to keep water and crud out.

The timing chain cover does have splash oil behind it (that's how the chain and gears get lubed). The cover has no gasket. It uses an anaerobic sealant to seal it.

[mieczkow]

Lee,

I did replace the rubber grommets on the valve cover bolts a few years ago. I also don't think anything is coming from the oil pump - I've been through that and am pretty familiar with the leak pattern for that - there is nothing at all on the pump. I seems confined to the extreme edge of the front timing cover where it meets the valve cover. I did replace the valve cover gasket a couple of years ago but maybe it is time to do it again. I had it apart to check the valve clearances about 6 months ago - maybe I damaged it when I re-assembled the cover and gasket?

Here's a picture:

I'm going to post one more picture in a second reply since it appears I can only upload one picture....

[mieczkow]

here's one more shot showing the lower surface. You can bead the bead of oil in this one.....

[moondog]

Just to clarify things, there are two timing covers.

There is the T shaped IGNITION timing cover on the crank cover side of the front of the motor. This cover bolts to the timing CHAIN cover. The ignition timing cover should have no oil behind it as there is an oil seal in the chain cover keeping oil from getting in. There is a gasket on the ignition timing cover, but that is to keep water and crud out.

The timing chain cover does have splash oil behind it (that's how the chain and gears get lubed). The cover has no gasket. It uses an anaerobic sealant to seal it.

Agreed but I guess this depends on how much oil is leaking. If it is seepage but not dripping, ok maybe the timing chain cover but if it is more than that I would go looking

[98lee]

The easiest way to find the source of the leak would be to thoroughly clean the area (a spray bottle of Simple Green works well), then go for a series of SHORT rides until the leak just starts to appear. Sometimes a light dusting of powder (on the area on the bike, not on you) before the ride will help show the leak especially if the oil is very clean.