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Old 1 Week Ago
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Strange crank markings?

Iím in the middle of a top end on the 250 and when I spun the crank a few times I noticed this funny mark on it? It almost looks like a rusty residue. What can it be? Anything to worry about? It feels smooth. Bike has 75hrs on it.

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Old 1 Week Ago
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Quote:
Originally Posted by bigberger View Post

1) Iím in the middle of a top end
2) What can it be?
3) Anything to worry about?
1) Get out before starting the motor or BigBerger will be a Schnitty,
2) Electrochemical dendritic growth.
3) It can be if enough FeO2 comes off the crank bells and goes through the mains/big-end/wee-end.
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Strange crank markings?

Quote:
Originally Posted by Nutty View Post
1) Get out before starting the motor or BigBerger will be a Schnitty,

2) Electrochemical dendritic growth.

3) It can be if enough FeO2 comes off the crank bells and goes through the mains/big-end/wee-end.


I thought you might know. Thanks Nutty.

So what causes electrochemical dendritic growth?

The surfaces feel like a babyís bum. Should I do something, or just slap back together and keep riding?
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Originally Posted by bigberger View Post

1) what causes electrochemical dendritic growth?

2) Should I do something, or just slap back together and keep riding?
1) A combination of electrolytic action in the sump oil load, moisture and static charge.

2) That's nothing to worry about. Think about these three things;

a) Don't restart the bike after washing unless you're prepared to ride it for at least 20 min. It's safer to do the filter and put it away cold.
b) Use a FULL syn premix oil.
c) Run a bond between the RHS crankcase half and battery negative.

This phenomenon is common on methanol/castor bikes and oil-injected bikes, also under the roof paint on LWB vans.

Use Motul 800T at 60:1 and it'll never happen.
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Ah that makes sense. I got a little water in the gearbox filler point a while back when it came loose on a ride. After flushing the gearbox several times, Iíve noticed a little moisture in the breather hose of late.

I recently bought some Castrol TTS as things are a little tight at the moment. Itís fully synthetic so hopefully it will be ok. Maybe if I win lotto I can afford the Motul - itís almost double the price! But I know, you get what you pay for.
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Nothing wrong with TTS, it's as good as all the rest!
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