Although I have two strokes much of the maintenance would be the same. Take off the wheels, swingarm, forks, steering column and then clean and grease all of the bearings. Change the fork oil and shock oil. Maybe even buy new springs for the suspension. Use anti-seize on every bolt that you take out. Disassemble carb and clean. Lube cables, bleed and/or change hydraulic fluid for brakes. The list goes on and on. I have five MX bikes that I worked on over the winter. Just finished putting my RM250 back together and 30 minutes ago. Race season should start for us in about two weeks.
BTW: WINTER SUCKS :moon:
Spring, summer and fall RULE because DIRT BIKES RULE! :thumb: