1981 GS750E engine oil leak below ignition cover

[eil]

Since I've had this bike, I've had this small but persistent oil leak near the bottom of the engine on the side. The result of this is that as I ride, I get a fine coating of oil on the clutch cover, brake pedal, exhaust cover, and various bits along the lower right side of the bike. It only appears to leak when the bike is in motion, not when at rest. (In other words, I never find a pool of oil when I walk up to the bike, only a drip at the most and even that much is pretty rare.)

Example:





At first I suspected the worst: that it might be leaking from the crank bearing/seal behind the ignition. But close inspection (thankfully) reveals that not to be the case. There is a smidgen of oil in there, but I think it's from getting blown/wicked up in there. Nothing like the amount I there would be if the leak came from there.

Here is where I think the oil is coming from:



That bolt below the ignition is a cap for some kind of port. (Is there where an oil cooler line would go?) Often when the bike is at rest, there's a little drop of oil hanging out there. I opened it up and found two o-rings: one on the cap, and one around what I guess is a plug:



I replaced both of these o-rings with new OEM ones and I'm still getting a leak. I'm curious if anyone has seen this before and what else I might try to seal it. I was thinking maybe a small flat gasket under the cap. Thought maybe I could cut one out an inner tube and try that for a ride or two just to confirm that the leak does indeed come from there and go for something more permanent afterward.

Thoughts?

[Nessism]

Sometimes these pesky little issues are a real pain...

Think you are on the right track by replacing the O-ring. Think you need to inspect the cap and case sealing surface carefully and look for scratches. Negative on supplementing the O-ring with a gasket. Find the root cause of the problem and go from there.

You might want to clean the engine really well with Gunk engine cleaner or similar, dry with leaf blower or what have you, then start the engine while you watch closely for the source of the leak. Some people use spray foot powder, the stuff with talc, on the offending area so you can really hone in on the source.

My first 850 had a similar leak that I traced back to one of the crankcase half screws. The screw wasn't the source of the leak, a sealer void between the two crankcase halves was, but the oil ran down the screw and then dripped off and onto the ground. In the end I removed the screw and installed a copper crush washer over the head and then reinstalled. This kept the oil inside the engine. Not the most elegant solution, but it worked.

[eil]

Alright, so further investigation reveals that the leak is probably coming from behind the ignition cover after all.

So give it to me straight, doc, how boned am I? Is this going to involve pulling the engine and splitting the cases?

The service manual makes no mention of a seal in this area, only general instructions for disassembly and reassembly are provided. However, I'm looking at the parts fiche for the crankshaft and I see an "oil seal" at part #11, 09283-30048. Is this what I'm after?

How careful must I be to not disturb the ignition timing when mucking about in there?

[Chuck78]

EDIT: I stand corrected, sorry for the confusion... Yes - do as Tom and Ray say, by all means.

[tkent02]

Why not just pull the seal and replace it?

[rapidray]

You can change that seal without splitting the cases or even removing the engine. Just remove the ignition, pull the seal, put some grease on the outside AND the inside of the new seal & drive it in. Call me at 714--356-7845 if you have questions. Easy to do.
Ray.

[hillsy]

Are you sure it's leaking there? I don't see ANY oil on the ignition plate or anywhere else inside the cover??

Degrease the bike and go for a short ride. You should see exactly where the oil is coming from after that.

[eil]

Thanks for the tips.

I did what hillsy suggested. Well, a modified version of it... To be sure the oil was coming from the crankshaft seal, I wadded up a bit of paper towel and shoved it in the void at the bottom of the ignition area. (Being careful that it didn't impinge on the advancer doohicky of couse.) I reasoned that if the top of the wad was wet with oil and none was found below or outside the ignition cover, then it had to be coming from that seal. Turns out it was. This also gave me a hint as to the rate of leakage... not much, thankfully.

So I guess I'm going to order a new seal.

Mucho thanks for the offer for direct advice Ray, I'll keep you in mind if I run into any snags.

From peeking around with a flashlight, it looks like that case sealer stuff is holding the seal in. Is that going to make the removal difficult? Do I need to apply it to the new seal upon replacement?

[posplayr]

Thanks for the tips.

I did what hillsy suggested. Well, a modified version of it... To be sure the oil was coming from the crankshaft seal, I wadded up a bit of paper towel and shoved it in the void at the bottom of the ignition area. (Being careful that it didn't impinge on the advancer doohicky of couse.) I reasoned that if the top of the wad was wet with oil and none was found below or outside the ignition cover, then it had to be coming from that seal. Turns out it was. This also gave me a hint as to the rate of leakage... not much, thankfully.

So I guess I'm going to order a new seal.

Mucho thanks for the offer for direct advice Ray, I'll keep you in mind if I run into any snags.

From peeking around with a flashlight, it looks like that case sealer stuff is holding the seal in. Is that going to make the removal difficult? Do I need to apply it to the new seal upon replacement?

It is a little tricky to change. Order a couple of the seals.

[bwringer]

It's not that hard to install the crank seal, if you've ever changed a seal before on a car or whatever.

Two hints:

1) The seal may need to be installed in a way that looks "backwards" to you (with the surface that you would normally think is "inside" to the outside). Inspect the seal carefully for a teensy tiny wee little atom-sized arrow indicating the direction of rotation near the inner lip. Get this wrong and it will be leaking again in short order.

2) Don't just bash the seal into place with a claw hammer. It's much easier to draw it into place with a long 8mm bolt into the crankshaft, a couple of washers and nuts, and a large socket or piece of tubing.

I generally coat the outside of the seal with a thin layer of case sealer, which is how they did it at the factory. As Ray indicates, grease works fine as well, and he's probably changed more of these than anyone.

[eil]

Questions:

1) The 12mm bolt on the end of the crankshaft, normal or reverse threaded?

2) Where do I get a 19mm wrench thin enough to hold the crank while I turn the other one? My current wrench is too thick am I very nearly boogered the 12mm bolt with my amateur actions today. (I have no impact wrench, by the way. I do have an impact driver but I'm not sure it's the right tool for this.)

[bwringer]

Questions:

1) The 12mm bolt on the end of the crankshaft, normal or reverse threaded?

2) Where do I get a 19mm wrench thin enough to hold the crank while I turn the other one? My current wrench is too thick am I very nearly boogered the 12mm bolt with my amateur actions today. (I have no impact wrench, by the way. I do have an impact driver but I'm not sure it's the right tool for this.)

1) It's an 8mm bolt -- bolts are specified by the length and diameter of the threads (8mm X 65mm thread in this case), not the wrench size or height of the head. And yes, it's a normal right-handed thread. Righty-tighty lefty-loosey.

2) You keep the engine from turning a different way. Put it in second gear and hold the rear brake.

DON'T use an impact -- break that bolt and you're in a world of hurt. You MUST get the bolt hot in order to soften the thread locker -- there's a thread locking compound akin to red Loctite in there. Use a propane torch very carefully, heat the head of the bolt (careful about the other parts in the area - remove the ignition plate first), and carefully loosen it by hand with your VERY BEST six point socket.

[eil]

Thanks to the help of ye merry gentleman, I got the seal replaced. Yay!

Now a quick question. I'm rapidly becoming knowledgeable about these bikes but ignition timing is something I'm fuzzy on. When I found the ignition plate, it looked like this:



But the service manual says to install it like this:



I did what the service manual said. (Haven't fired the bike up yet, but will tomorrow.) Is there a reason the PO would have set the plate as per image #1?

Does the ignition timing need to be fine-tuned on a GS with an electronic ignition? With a timing light and such? If so, can someone point me to a guide on this? (Didn't see one on basscliff's site.)

[mrbill5491]

There is no real timing adjustment, maybe a degree or two, it's pretty much preset from the factory. Just line up the lines and go ride.

[eil]

Thanks for the reply, MrBill.

This morning I was paging through the manual and did find the timing instructions. So yet another noob moment from me.

I will probably go out to HF later today to get a timing light so that I can learn how to use it and verify the timing for sure.