Black oil after one ride

[ktm200]

The engine is a KTM 200, 2-stroke. After putting in new main bearings, seals, rod, piston, rings, and cylinder coating, the oil comes out black after only a two hour ride.

The change in used oil color is new since the rebuild.

The cylinder was sent out, with the new piston, to a reputable outfit for nickasil plating.

Any ideas are appreciated.

 

[IndyIan]

You must mean transmission oil? 2 strokes have no engine oil other than what's in the gas. All your engine work has nothing to do with your transmission oil.
Are you using transmission oil? Make sure of that first.
I don't really recall having my gear oil darken up that quickly. Maybe your clutch is wearing fast?

 

[hate2work]

What oil are you talking about?

 

[sunruh]

considering that the tranny oil on a 2smoke does not come in contact with the gasses of the engine, there are only a few answers:

1) the crank seals are shot (allowing said engine gasses to contaminate the tranny oil)

2) your clutch is toast

while i greatly recommend ATF type F oil, usually any oil will work in the tranny. usually one is recommended to use something that handles the shearing the gears will place on the oil.

 

[heavyhitter]

Drain it fill it with ATF. When you check it again it should be red. Smell it and see if it smells burnt.

 

[ktm200]

Yes, I mean the transmission oil.

If the crank seals, which are new, are shot is there a second event other than black transmission oil that I can reference? It would be nice to triangulate.

 

[IndyIan]

I imagine idling the bike with the fill cap off the transmission will tell you how the seal is doing. Air puffing in and out would suggest to me a bad seal to me. Also gear might be pulled into the engine and not burning to well leaving oil in the pipe?

 

[ktm200]

Thanks, guys, I'll take a look.

 

[Mackelroy]

 

[BMWR1150GS]

Was moly assembly lube used for the rebuild? If so, it turns oil black quickly...if that is the source of the blackness, no harm...keep it in there...moly is very tough stuff and gears love it...engines do too. But a 2-stroke needs no moly, especially a Nikasil cylinder...