Black, stinking fork oil

I've been stripping the forks on my SV this afternoon. I have shiny new Racetech cartridge emulators and springs to install, so needed to get at the damper rods to drill out the compression damping holes. Besides that, one fork seal has been weeping lightly, so I've had a new set of oil and dust seals sitting on my desk for a month. I cracked open one damper tube retaining bolt and shortly the oil began to drip out. It was jet black and stank like *badly* burnt engine oil! It wasn't that colour when I put it in. I found thick slimy deposits of the stuff inside the bottom of the sliders. It wasn't a paste as a result of wear, but looked like a slime as a result of something, probably plastic or synthetic rubber, having disolved. Having cleaned all the parts, I couldn't see where it might have come from. I hoped the other leg was OK so I could compare the components. No such luck, the other leg was the same. Now, I've changed fork oil on this bike several times before and never seen this.

So, these questions are aimed at those of you who've stripped SV forks before. Besides the oil seal and damper rod piston ring, is there anything else in the forks which is supposed to have black rubber or plastic as part of its construction? Is the damper tube's oil lock piece solely made from hard white plastic? It is in my forks. Likewise, inside the lower end of the stanchions, there's a device that's free to move around, but not up and down the tube. What's this do and should it have rubber or similar in it? Help!

When I stripped my forks a couple of weeks ago to fit the hyperpro springs, I must dmit they stunk a little funny but the oil looked fine. I dark honey color with no bits in. And they were 3 years old.

Sounds like the seals werent seated properly and something has ingressed in through them. I know mixing stuff like water with brke fluid cn mke it turn funny so maybe fork oil is the same?

[fizzwheel]

I think you have all the bits identified correctly and they seem to be as I remember them when I took mine apart.

My oil stank it was gross, it was really thin like water, dark grey in colou and also it was contaminated with water as well. It smelt disgusting, a bit like fish guts, it really was horrible.

Both my oil seals were blown and I just put it down to the fact that water was getting in there and had been doing so for a long time which is what caused the stink.

Was the side that stank and has the slime the same side that the oil seal was weaping on ?

Originally Posted by fizzwheel

Was the side that stank and has the slime the same side that the oil seal was weaping on ?

Both sides were the same; the one that leaked and the one that did'nt.

think how much use pounding the fork oiltakes..... yes it is bad.. i once strippedfor the first time some nsr250 12year 30k old fork... good god i almost heaved!!!!!!

Originally Posted by chazzyb

So, these questions are aimed at those of you who've stripped SV forks before. Besides the oil seal and damper rod piston ring, is there anything else in the forks which is supposed to have black rubber or plastic as part of its construction? Is the damper tube's oil lock piece solely made from hard white plastic? It is in my forks. Likewise, inside the lower end of the stanchions, there's a device that's free to move around, but not up and down the tube. What's this do and should it have rubber or similar in it?

I know it's bad form to answer your own posts, but hey, I'm not perfect . It seems there aren't any components in the SV forks which could have made this mess. That leaves only the oil having degraded so badly. It was so bad it had stained various fork internal steel parts - springs, spring spacer tubes, etc. The oil had 'only' been in there for two years/10K miles. This was Motul fork oil, bought from H-G. I shan't use that again.

[Spanner Man]

Good afternoon.

There's nothing rubber in there that could break up. So it was most certainly rather solid gunge. I have scooped what appears to be grinding paste from forks in the past.....Smells lovely doesn't it?

Cheers.

Damn people, I have to change my fork oil at least twice a year. It just goes away so fast if you ride very aggressively. Just think how much those little forks move up and down. It cooks the oil. When the front tire is toast so is my oil. I can't believe you all leave it in that long, holy crap. I can feel it when it goes off, the damping goes away.

[Spanner Man]

Originally Posted by Jimmie

Damn people, I have to change my fork oil at least twice a year. It just goes away so fast if you ride very aggressively. Just think how much those little forks move up and down. It cooks the oil. When the front tire is toast so is my oil. I can't believe you all leave it in that long, holy crap. I can feel it when it goes off, the damping goes away.

That's because we're all tightar5e Limeys mate!

Cheers.

Nah, forkoil is quite delicate and fragrant.


Used gear or diff. box oil, now thats just bloody awful.