Final Drive Oil Color Analysis

[MirrorrorriM]

So I just got back in from tweaking carbs and such and thought while I was waiting for the bike to cool down, I would check the fluids. I have never checked the gear oil before, and when I took the fill cap off, I noticed the pumpkin was full, but the fluid was kind of milky/light brown, which seemed odd to me.

I decided to play it safe and drain it all out. I didn't grab a picture, but this one from google is what it looked like after it drained out:




I've done two differential changes in cars, and I have never seen diff fluid come out light brown like this. Is this an indicator that the previous owner somehow found a way to get water in there?

This is mostly just out of my own curiosity, as I haven't had an issue with the final gear thus far. No grinding, no leaking, no chattering.

[WintrSol]

Sure looks like he rode through a creek, to me. Maybe he left it out in the rain after it was hot from riding, and sucked the rain in through the vent.

[MirrorrorriM]

My fear is that I've owned it for over a year now and the fluid has probably looked like this for some time =O

[Dodsfall]

I've never seen gear oil that color before either. I'd suspect water.

Changing it out was a good idea.

[MirrorrorriM]

Originally Posted by Dodsfall

I've never seen gear oil that color before either. I'd suspect water.

Changing it out was a good idea.

Thanks Dods. I'll just have to keep an eye on it and make sure there's no more discoloration in the future. I guess this is why people say to change out the rear gear oil when you don't know the history of the bike. One bottle is only $5 and that will last you multiple gear changes.