Oil inside Belt Housing

Hi,

I have an oil leak beyond my pay grade and it's headed for a mechanic (I have a good one in town). But first, I'd like to get as smart as I can, because, well, a stealership is a stealership. I'm guessing I have a worn seal somewhere.

I keep my 2012 Silver Wing pristine clean. A few days ago when cleaning the rear rim I noticed oil residue. It was streaked, almost like it was thrown into a fan (the motion of the rear tire?). I cleaned it off the rim (and washed the tire rubber for good measure), rode the bike and it appeared again. This time I noticed a few drops of oil on the ground below the rear cover, almost microscopic.

I took the three covers off and found a good amount of dried oil inside, so this had apparently been occurring for awhile. I did not see any "live" oil (wet). The closest thing was a bit of oil in the grooves in front of the clutch spring.

The belt looked good. The variators are fine. The bike runs like a champ. I cleaned the daylights out of the rear cover interior and put it back together.

A bit of history if it helps with anyone's possible diagnosis. It's a Florida bike since it was new. I bought it in July '18 with 1,600 miles on it from a NASA engineer (complete with a hard copy of the service manual). Even though it was barely used the oil and filter had been changed regularly. I immediately changed the coolant, brake fluid, final drive oil and oil and filter. The bike now has 6,200 miles on it and has performed flawlessly, without a single hiccup of any kind.

(Sidebar: for convenience, I added a tall GIVI windscreen, a Corbin seat in "bomber jacket red" that I put on this week, and a power socket for GPS on a RAM mount.)

So, any ideas? Like I said, I would guess there's some kind of seal involved. I want to get the leak fixed because I don't want to clean the rear rim after every ride, partly because I fret about oil getting on the tire.

Any thoughts are appreciated. This is my third Wing (had two 2003's) and I want to keep it in tiptop shape for years to come.

Mike

One more photo: this shows the oil caked on the interior of the rear cover. Photos in the first post show the "drain point" where the oil exits the bike and hits the ground (after cleaning) and the clutch spring before cleaning -- you can see oil splatter on the large rim around the perimeter. The three tracks in front of the spring are where I saw wet oil (I think ... it was barely discernible).

There are only two seals in the belt case which would cause that problem. Unfortunately neither of them are simple to access. The first is the crankshaft seal, located behind the variator assembly. To access it requires removing the swingarm (six bolts behind the variator --DO NOT remove the big snap ring holding the swingarm bearing), which also requires removing the rear wheel, shocks, the center piece attaching the L & R swingarms, then dropping the swingarm & final drive as one assembly.

The second seal is behind the clutch bell. And though it is "easier" to access it requires a Honda special tool to remove the clutch bell. In the absence of that tool it is possible to remove the final drive gear box cover, input shaft & clutch bell via the holes in the clutch bell and then press the the clutch bell off the shaft with an arbor press. But don't be discouraged, here is a link to an earlier post detailing removing the clutch bell using a modified gear puller.

https://www.silverwing600.com/t10987-clutch-bell-how-to-remove-replace?highlight=Clutch+bell

Good luck, and please let us know how you sort out this leak.

Tim

Tim,

Wow, you know your stuff. Thanks for taking the time to share that.

By way of a 'lateral thought' is the gearbox vent pipe clear ?

Are we to assume you did not open the drive cover when you changed the rear drive oil ? Reason being, I'd say the culprit is probably your drive oil fill which could have leaked tiny amounts of drive oil, which coupled with belt debris would look like the last pic on your post. Besides, it is the closest culprit.
However, I am no mechanic. It's just that the bike is 7 years old, lightly ridden till now.
I also noticed that the belt has a good size chunk missing in the last pic !

Jay.

I will check the vent pipe. As to the final drive oil change, you are correct, Jay. I did not remove the cover, although I will with future changes, having realized how easy it is. That said, I changed that oil eight months ago in July and after cleaning the interior of the case to like-new condition yesterday, I still have a tiny leak this morning (not a hint of oil by the final drive fill and drain plugs btw).

Once I get the leak solved I will put a new belt on, and probably Dr. Pulley 24 gram sliders.

I am within striking distance of needing a new rear tire — also found a nail in it last week — which, as Tim said, will make changing the crankcase and/or seal behind the clutch bell easier. I plan to remove the three covers before the mechanic starts work — why pay $110 an hour for that?

Any other possible culprits for the leak? Am I right in thinking it’s likely a seal?

Update and a big question:

After a 40-mile ride in the evening and another in the morning, I opened the three covers to see inside the belt case. Not a drop of oil anywhere. However, I still had a bit of oil spatter on the rear rim, and a drop hanging outside at the lowest point of the belt case (the location is shown in the photos above; one dirty and one clean).

Examining this from the other/right side of the bike, I noticed a small open hole on the bottom of the case (photo attached, after I cleaned the oil off). The hole appears to be there on purpose, engineered for something.

There was wet oil residue around the bottom of the hole. I gently probed a Q Tip up inside it and it came out oily. It's located over the rim, which might explain the spatter effect if oil falls down and is whirled around by the motion of the tire.

What is the purpose of this hole, and what might it tell me about the leak?

Thanks.

It could be a weep hole for the final drive output shaft (rear axle) seal.

Seems to me another member a while back posted about a drip at the same location. The fix required the swing arm/final drive to be removed, the gear box disassembled, then the output shaft bearing be extracted in order to replace the internally-mounted seal.

Somehow I can't imagine that seal leaking would find its way into the belt case.

"Somehow I can't imagine that seal leaking would find its way into the belt case."

I believe you're right. The oil inside the case was ancient and caked, possibly the result of the first owner overfilling the final drive oil so it seeped into the case.

I'm thinking the "weep hole" oil is entirely separate. And unfortunately, more in line with the elaborate fix you cite.