After hitting 18,000 miles, I started to think about what original parts would start to go. In general, the engine runs great! It’s never given me any serious issues, but I didn’t want to ignore things until something in the engine failed that could create unfixable damage. The first thing that seems to go based on other’s insight is the cam chain tensioner, because the tensioner rests on a rubber cap, it tends to dig in, which lessens the tension, which can potentially cause the timing chain to skip a tooth, which could bend valves and cause serious damage. There are aftermarket versions that are heavy duty, but I decided to stick with OEM parts. They were cheaper, about $30 for a new tensioner and rollers, and since my engine is stock bore there’s no need for a tougher tensioner.
The install went pretty smooth, I took some extra precautions like I did with the cam install by zip tying a few places to make sure the chain didn’t move at all and get off timing (obviously I checked it after finishing up, but still).
The old chain tensioner was actually in pretty good shape! Didn’t find any rubber that was shredded off, I’ve seen from others that the rollers can disintegrate after a few thousand miles, let alone 18k. The tensioner cap was definitely indented though, so it was worth it to replace that.
So I put everything back together, check the timing once again, and even checked the valves. Start it up and I hear some nasty noises. I immediately shut it off and start pulling the cover off. I take it apart again and double check everything, didn’t see any issues. Since everything was apart again, I oiled up the cam chain, checked the torque on the tensioner arm and the lower roller, and put everything back together as carefully as possible. I go to start it up again and…..same noise.
I’m feeling pretty defeated at this point, racking my brain as to what could be wrong. All I did was replace the cam chain tensioner! As I’m thinking about this, I let the engine continue running. 20 seconds or so go by, then the noise is gone! Since I drained the oil before doing this, my guess is that the oil hadn’t made its way around the engine quite yet. Still, I took it on a careful ride and listened for any change in the engine sound. After 50 miles of careful riding and another timing check I think all is well!