I just wanted to share something I found tonight on my bike so others can be made aware of what to look for and react accordingly.

I discovered my rear sprocket hub assembly has moderate to severe inter-crystalline corrosion in two locations. Inter-crystalline corrosion is essentially a separation of metals along its natural grain boundary and by definition is the worst kind of corrosion you can experience as it will very severely diminish the strength of the material and can and will cause structural failure of the component.

When I pulled the sprocket mounting bolts from the rear of the hub, they were pure white with aluminum powder corrosion so I began a detailed inspection of the part. After cleaning it with solvent it looked like the below photos. I know it doesn't look horrible but you can see the cracking in the material, much like you'd see in dried mud.

Having my hub potentially separate on me at speed is not a comforting thought so it will be replaced. My bike is a 1994 so I wouldn't expect to see this kind of damage on newer bikes, but similar years please take note.

I believe this came up a few months ago.
They all look like that. That's just crazing from the casting process.
Looks just fine. Everyone I've seen has that surface wrinkles or lines.
If you feel better getting another one, that's OK.

looks like surface scale, if the part was forged, it would make sense.

if you want to do some destructive testing, put it in the vice and get the hammer and cold chisel into it. i think you'll be surprised just how solid it is.



****edit*****
i see addidas pointed out it's a casting... that's even worse to show miniature cracks, that aren't really cracks.

either way, personally if i didn't trust it i'd hammer on it some to see if i was right.

I put the hammer to it a couple of hours ago and it did hold. Maybe I'll bring it into the NDT testing guys at work and have them check it.

I think someone once took a file to it and found the were just surface wrinkles. They didn't go any deeper than what sand paper would take off.

Get another one. Then hit this one with a hammer or slice through it with a diamond saw and report back.
Lots of parts get some white dust on them. Especially some of the bolts like handlebar bolts (I've taken apart lots of GS500 stuff). Probably due to natural crap in the rain and weather like salty winter roads. The worst it has ever done is make it really really hard to take things apart. My Eastwood vibrating parts cleaner makes everything look like brand new again. I love that machine!