2 Stroke gearbox oil...

no_shad · Trackday Trickster Joined: 17 Apr 2005 Karma :

Oil will always go black over time as the repeated heat cycles take it's toll on it.

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

Oil gets black from shit getting into it, not from the repeated heat cycles. I've drained 10k mile old fully synthetic oil from a car with 90k on the clock and its looked brand new.

So yoko. Was the old oil very dirty? When you drain it a fair amount stays trapped in the assorted nooks and crannies, of which there are many in a gearbox. If the old oil was very dirty the new oil get dirty quickly.
Or it could be a crank seal leaking a bit, but I'd expect that to burn some oil too.

If it bothers you, change the oil again and monitor it.

no_shad · Trackday Trickster Joined: 17 Apr 2005 Karma :

Guest · Brolly Dolly Joined: 22 Apr 2004 Karma :

I was told (by a lubricants specialist) that modern oils soon go black as they hold the contaminents in suspension. You should worry when they turn clear again as they've stopped doing their job.

DimmniBurek · Renault 5 Driver Joined: 26 Mar 2005 Karma :

I have changed it with Motul Transoil and it is the same colour that it was the day I changed it
Motul is the best!
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Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Suspect it is as Robby suggests and just rubbish left in there from the last lot of oil. You will get some contamination from the friction material on clutch plates.

My understanding is that the main reason oil discolours is the build up of contaminants held in it, mostly carbon blown past the rings on combustion.

Think it is Amsoil that recommends very long oil change intervals and fairly short filter change intervals using their filters which are designed to filter down to a smaller size.

Could well be that some of the contaminants are burnt engine oil, but that is probably a small amount burnt on the walls of the cylinder.

All the best

Keith
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krueger1 · L Plate Warrior Joined: 19 Nov 2005 Karma :

Go here and read up >>>
https://www.amsoil.com/storefront/SearchResult.aspx?CategoryID=237

also >>> https://www.amsoil.com/storefront/tdr.aspx

ALSO >>> www.5W-30.com
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