Rust on my shock

[Gonzo]

Normally I'd not worry about a bit of tinworm on a shock, but when it's on the chrome bit wot the oil seal slides up and down on, it's a bit different. It's obviously on an ohlins shock, and I was wondering if they do a spare parts service as their site's about as much help as a chocolate fireguard...

Anyone else suffered with this?

 

[Dave]

If it's not leaking I'd ride with it until you can find a used shock.
A rusted shock shaft isn't too common anymore - my brother's '92 Ohlins looks perfect.

 

[MattR]

Gonzo,

Rust and/or other imperfections (like pits, dents, wear, etc.) on the shock rod will cause oil leakage. The seal can be easily damaged by anything on the chrome surface. Like Dave mentioned, ride it until it leaks... just don't be too surprised if it happens rather fast. Trust me... I am a suspension engineer (in the auto industry) and deal with shock leakage issues from rod imperfections all of the time.

I recommend sending your shock to someone for a rebuild and get a new shock rod. It will be good as new and cheaper than replacing the entire shock. If you have the proper tools and access to nitrogen gas, you could do the work yourself... but in my opinion it is more cost effective to let a professional (such as LT-Racing) handle the shock rebuild.

By the way, I noticed your other post regarding your seized engine. I wonder if the previous owner left the bike sit around a long time. The presense of rust on the shock rod (which is rare) may be an indication of corrosion on others components such as cylinder wall... leading to premature engine seizure. Just a thought.

 

[Gonzo]

Yeah. I would send it away for a rebuid, but funds are tight at the mo. and LT-Racing is on the other side of the world to me! It's far enough down the rod that it's not gonna cause problems once I wind the spring up a bit. I reckon it was probably caused by a stone chip that was left to fester. And yes, it doesn't look like it's had a huge amount of use. There's bits of rust here and there.

On the engine side of it, I've pulled the top end apart and the clutch cover off, and it seems as though the crank bearings have collapsed. Why is anyone's guess.
The bore is fine bar a few small lines along the front, so I might send it for a light hone and get some new rings, the water pump gear looks a bit chewed and half a tooth is missing, other than that, everything else is fine, but the crank won't turn!