Be sure all the fluids have been renewed. In addition to engine oil, be sure the coolant, and front & rear & clutch brake fluid are new.
--Valve clearance check is important.
--When you change the tires, renew the valve stems.
--Check that the radiator and oil cooler are clean on the exteriors.
--Examine the chain and sprockets for wear & clean under the front sprocket cover.
--Examine the thickness of the brake pads.
--Check that the rear sprocket is aligned straight with the front sprocket. --When you have the rear wheel off, check that the rubber dampers are tight enough to hold the sprocket carrier in the wheel hub when you turn the wheel over.
--When either wheel is off, check that the wheel bearings and sprocket carrier bearing turn by hand absolutely smoothly and silently. (Any sign of dry red rust from a bearing or chain link means that its dead.)