[Unusual Suspect]

Hello all, I noticed a small oil spot at the rear left of my bike. After investigating, I tracked the source to where the drive shaft meets the drive gear At the rear wheel. It looks like grease is coming out from inside the gears, and being spun out. It’s a dark olive green grease that hardens when cold. I have cleaned it all out as best I could, and will keep checking to see if more comes out. I’ve only had the bike about 3 months, and I’ve put about 3,000 miles on it so far. I didn’t notice this before now, but that doesn’t necessarily mean it wasn’t there. I’m thinking it could be final drive oil that was overfilled and is leaking up through the gears? I have looked through the service manual and can’t find any other place where there is grease or oil in this area. Is this a seal or O ring that’s malfunctioning? Or would this be “normal” if the final drive oil was overfilled? She rides just fine, no issues there. And I checked the final drive oil, and it is filled to where it should be, and looks clean (I had the Honda dealership do some routine maintenance when I first got her, and this was one of the fluids they changed.) Any help would be greatly appreciated. THANKS!!

 

[Kbuskill]

That is the grease they put on the driveshaft before inserting it into the final drive. It could be that they put an excessive amount and it slung off.

It is definitely NOT coming from the final drive as the gear oil used in the final drive is much thinner... 80W gear oil.

If that grease was hot enough to liquify and drip then I would definitely check the level of the gear oil in the final drive.

To do this set the bike on its side stand on a level surface and remove the filler plug. The gear oil should be at the bottom of the filler plug hole. If it is low, top it off and keep an eye on it.

 

[Unusual Suspect]

That is the grease they put on the driveshaft before inserting it into the final drive. It could be that they put an excessive amount and it slung off.

It is definitely NOT coming from the final drive as the gear oil used in the final drive is much thinner... 80W gear oil.

If that grease was hot enough to liquify and drip then I would definitely check the level of the gear oil in the final drive.

To do this set the bike on its side stand on a level surface and remove the filler plug. The gear oil should be at the bottom of the filler plug hole. If it is low, top it off and keep an eye on it.

Thanks, Kbuskill. I will keep an eye on it. I have checked the final drive oil and it is fine. However I went ahead and ordered some more to have on hand, just in case. Thanks for your quick reply.

 

[Unusual Suspect]

So after about 3 weeks, it’s still leaking. I cleaned up the sludge that was there and replaced the gear oil with new synthetic final drive oil. What’s coming out now is thinner, but still has that green tint it seems to me that the first, thicker sludge was metal shavings or maybe dirt from the first break in period of the bike, mixed with oil. Now that it’s cleaned out, it’s just the oil. I’m thinking it’s an oil seal that is slowly leaking, but the oil level is still fine. Maybe over filled? And slowly leveling off. I went ahead and ordered new oil seals, but the manual says to use special oil seal fitting tools. Has anyone ever replaced this oil seal? Is it possible to do without the special tool? I need to replace the rear tire soon anyway. And I thought while I have the wheel off I would attempt to replace this seal. Any suggestions would be greatly appreciated. Thanks!

 

[krashDH]

So after about 3 weeks, it’s still leaking. I cleaned up the sludge that was there and replaced the gear oil with new synthetic final drive oil. What’s coming out now is thinner, but still has that green tint it seems to me that the first, thicker sludge was metal shavings or maybe dirt from the first break in period of the bike, mixed with oil. Now that it’s cleaned out, it’s just the oil. I’m thinking it’s an oil seal that is slowly leaking, but the oil level is still fine. Maybe over filled? And slowly leveling off. I went ahead and ordered new oil seals, but the manual says to use special oil seal fitting tools. Has anyone ever replaced this oil seal? Is it possible to do without the special tool? I need to replace the rear tire soon anyway. And I thought while I have the wheel off I would attempt to replace this seal. Any suggestions would be greatly appreciated. Thanks!

Mind sharing what section you're looking at? I'm looking in the final drive section but I'm not seeing much on the universal joint end seal...which is where the final drive shaft connects to. I can likely make a suggestion if I know where you're looking in the manual.

 

[Unusual Suspect]

Mind sharing what section you're looking at? I'm looking in the final drive section but I'm not seeing much on the universal joint end seal...which is where the final drive shaft connects to. I can likely make a suggestion if I know where you're looking in the manual.

14-20 and 14-21 the oil seal here says it uses a special “oil seal driver” tool to fit it in place. I think I’m reading this right, and this is the oil seal inside of the final drive gear case, where the oil is leaking from on my bike. It’s the last line of defense before the case opens up to the outside, and where the gear case meets the drive shaft. I’m not terribly worried about it because the oil level seems to be relatively stable, and the gear case gets warm, for sure, but not too hot to touch for 8 to 10 seconds right after hard riding. I think it’s doing it’s job nicely, just a slight leak? Thanks for your suggestions.

 

[krashDH]

14-20 and 14-21 the oil seal here says it uses a special “oil seal driver” tool to fit it in place. I think I’m reading this right, and this is the oil seal inside of the final drive gear case, where the oil is leaking from on my bike. It’s the last line of defense before the case opens up to the outside, and where the gear case meets the drive shaft. I’m not terribly worried about it because the oil level seems to be relatively stable, and the gear case gets warm, for sure, but not too hot to touch for 8 to 10 seconds right after hard riding. I think it’s doing it’s job nicely, just a slight leak? Thanks for your suggestions.

No wonder I was thinking about the other side (grease) not the actual final drive gear seal. Don't know why I confused that.
You an probably get away with using a PVC tube that presses on the correct part of the seal to tap it in. Done that plenty with oil seals. You could also using a wheel bearing kit, they have a lot of handy adapters that fit seals.

You'd have to take note of the depth, I'm not sure if that Honda tool sets the depth of the seal or not, or if there is a machined surface that it seats in.

 

[Unusual Suspect]

PVC pipe. That’s a brilliant idea. I’ll give it a look when I get the rear tire. Thanks!

 

[Unusual Suspect]

So I just wanted to post a follow up in case anyone else has this same issue down the road. I believe this oil was coming out through the final drive gear due to being overfilled. When I first got the bike I took it to my local Honda shop and had them do the recommended maintenance, including changing out the final drive oil. They must have significantly overfilled it. I have since changed the gear oil three times myself and have yet to duplicate the error. I tend to be on the conservative side, so I will fill it up to the high side of recommended to be sure it is full. Haven’t had the slightest problem since. Again, to be clear, what was different about my issue was that the excess oil was leaking from the shaft drive side of the gear case, out into the boot that covers it on the inside facing the rear wheel. Others have reported a similar leak from being overfilled, but theirs came from underneath or even the back of the drive. Hope this helps someone.

 

[krashDH]

I wonder if their procedure was incorrect. If I remember correctly the proper fill height is with the bike on the side stand, fill until oil comes out of the fill hole. If they had the bike on a stand level when they did that they could have over-filled, but not grossly over-filled.

 

[Unusual Suspect]

I wonder if their procedure was incorrect. If I remember correctly the proper fill height is with the bike on the side stand, fill until oil comes out of the fill hole. If they had the bike on a stand level when they did that they could have over-filled, but not grossly over-filled.

Yes I believe you’re right about the proper procedure. Definitely supposed to be on the side stand, then fill till you reach the threads. I have read here that it works out the same if the bike is on a lift when you fill, but it should not be straight up on the ground with the weight of the bike on the rear tire when you fill. I’m just happy there’s no more leak despite my changing the gear oil three times since then. The more I do to this motorcycle, the more I love it. From regular maintenance to mods. It’s slowly becoming “my bike”. Thanks for your help.