What's the issue here? Oily spark plugs

[itchy worms]

Bought a 2001 M900Sie last month for cheap. Extremely cheap. But the owner said it didn't have any issues before. I even brought a trusted mechanic with me so I wouldn't waste money. Unfortunately tho, the issues are slowly starting to appear now. Every 5 miles, I check the spark plugs and they come out dark and oily. I thought it was an issue with the old spark plugs at first so I threw in brand new NGKs and fresh coils. I'm not sure what this is... Anyone had a similar experience? Would love to hear your thoughts before anything else.

 

[Joe Goldberg]

Bought a 2001 M900Sie last month for cheap. Extremely cheap. But the owner said it didn't have any issues before. I even brought a trusted mechanic with me so I wouldn't waste money. Unfortunately tho, the issues are slowly starting to appear now. Every 5 miles, I check the spark plugs and they come out dark and oily. I thought it was an issue with the old spark plugs at first so I threw in brand new NGKs and fresh coils. I'm not sure what this is... Anyone had a similar experience? Would love to hear your thoughts before anything else.

Hey, I'm worried this might be some serious oil blow-by or maybe worn valve seals. I don't really know how to help with that. Dark oily plugs ain't good news, man. Have you watched Final Destination 2 or something?! Anyway, you might wanna check the compression and look for leaks before spending more.

 

[coldplayed]

If your plugs are coming out oily even after new plugs and coils, its likely oil leaking into the cylinders,, could be worn rings, valve seals or a crankcase vent issue. I'd get a compression or leak down test to figure out whats really going on before things get worse

 

[thiago_tavares]

Black spark is to many fuel and few air, the classic adjust.
But, with oil, could be piston rings or valve seals, isn't seriously if is starting now, and is it not difficult to repair at home (if you have the basic skills and tolls)

 

[CrashedBandit]

Bought a 2001 M900Sie last month for cheap. Extremely cheap. But the owner said it didn't have any issues before. I even brought a trusted mechanic with me so I wouldn't waste money. Unfortunately tho, the issues are slowly starting to appear now. Every 5 miles, I check the spark plugs and they come out dark and oily. I thought it was an issue with the old spark plugs at first so I threw in brand new NGKs and fresh coils. I'm not sure what this is... Anyone had a similar experience? Would love to hear your thoughts before anything else.

Every 5 miles? Man it really takes you a long time to get somewhere )) All jokes aside, most of the recommendations you got are pretty good, it's some kind of rubber that's bad and leaks oil where there shouldn't be any. I don't want to put salt on a wound, but there's a reason why the bike was so cheap and I'm 99% sure the previous owner knew there was a problem. Maybe he didn't knew what the exact problem was, but he knew.