Problem with one-way clutch

My exercise bike has a one-way clutch that resembles a roller bearing.
The problem is that sometimes when the clutch engages it makes a loud
pop as it slips a bit. What is the proper way to clean and lube? the
rollers? There is a oily/greasy looking substance on the rollers and
clutch surface (hardened steel).
When the pedal crank is turned, the clutch engages to turn the
resistance flywheel. Uneven pedalling causes the clutch to
engage/disengage repeatedly, sometimes with a loud pop. When it
engages and then pedal pressure is increased, it may slip a tiny bit,
causing the pop as it re-engages. When you stop turning the pedal
crank, the flywheel coasts to a stop. There are no other unusual
noises (grinding, scraping, etc.)
The clutch surface is smooth and shiny. What I can see of the rollers
looks good as well.