Type or riding: Big grass fields and forest.
Hours/year: 50-60
Level: beginner
Bike model & year: Crf250r 05
Engine
Air filter: every 2 rides
Engine oil: every 8h
Engine oil filter: every other oil change
Trans oil: same as engine oil
Coolant: every year
Valves: 80h, new valves has only gone 8h
Piston rings: 80h
Piston: 80h
Crankshaft:120
Crankshaft bearings:90
Timing chain: every piston change
Chain tensioner: 200h
Engine seals: 200+h
Engine & trans bearing:never done
Clutch disk: Never done
Suspension/Wheels never done
Fork/Shock oil: 75h
Fork/Shock bushing and seals: 75h
Swingarm/Linkage/Steering/Shock/Wheel bearings: when they start to be bad
Brake fluid: when brakes doesn't brake good with new pads
sorry for the lack of info but I'm trying my best