bought this bike two years ago. Runs fantastic, have had a blast on it, but now I'm nearing 4k miles on it and I'm thinking it's time for a winter rebuild. This last summer it has started using quite a bit of oil. The oil is not going into the tranny, seems to be getting used up in the motor itself (out the exhaust valves or even burned in combustion). Don't have any oil residue out the pipe or anything, but it sure disappears each ride. Just yesterday I started getting a loud "ticking" sound on the left hand side of the engine that seems to be coming from the cylinder area. The sound is lower than the head. Maybe cam tensioner? Anyway, planning on tearing it down this winter, so what should I plan on for parts? Valve guides? cam tensioner? rings? etc. I know there are some better aftermarket choices on some parts, so what do you guys suggest? Thanks.