Back about 10 years ago, I took my TRX300 to a privately owned local motorcycle/ATV shop close to where I live for an oil & filter change and to also change front and rear diff fluids. Shortly after I got it back from him a noticed the valves slightly rattling. I took it back for him to adjust the valves.
For a good while after getting it back from adjusting the valves I noticed the 300 just didn't seem to run right like it was down on power. I eventually took it to a nearby Honda shop. They readjusted the valves put a new sparkplug, plug wire and coil. The Honda shop said the valves had almost 0 valve lash. Convinced the 300 was "right" after this repair a rode the 300 for several years, mainly just Deer hunting and when it snowed.
Since this time last year I have been going on a couple rides in the NC mountains and a ride in WV on the outlaw trails with a group of friends. After this past weekends ride in the NC mnts, the 300 was really rattling bad after riding it pretty hard all day. That's when I decided to tear it apart for a better look at the cam, rockers and valves. That's when I found this mess.
If I had to guess, the guy that changed the oil & filter for me, installed the filter in backwards and once he found out he messed up, he flipped the filter around right and gave it back to me.
The cam journal is so badly worn, I now know it wasn't the valves rattling, it was the cam rattling in the head. The cam was sitting in the head at such an angle, it wore the cam lobes on one side and also the rocker pads.
I have ordered a used head and head cover from a guy in Texas (ebay) and they came in today and they look great for used parts. I going to also replace the old valves, valve springs and of course the camshaft. I probably going to go ahead and replace the piston & rings with a Wiseco .50mm over sized piston and have the cylinder bored while I have the 300 torn down this far.
