Say what? The electric fuel pump is in the gas tank. Just what kind of a shaft would run from inside the tank to the oil pump ???I understand that the fuel pump/oil pump are on the same shaft and are notorious for blowing a bearing. My friend with 8 Beemers has his K100 torn down as I type this for that very problem.
Hope this helps and you get it fixed and achieve all the wonderful things you want in life. Have a nice day!
After nearly 200,000 miles of K bike experience my guess is that he simply needs new spark plugs.