KLR650 Unnerving Engine Rattle
My daily rider is a 2014 KLR650. I've put a little over 66,000 miles on her over the past few years, and although I've kept up the maintenance as best I can ... she's getting a little noisier in her middle age.
Recently, a rattle has been becoming more and more apparent, to the point now where it's quite noticeable most of the time. It seems to sound in time with the engine, maybe like a chain rubbing against something, but doesn't appear until you begin to rev up — it's completely absent while idling. The most mysterious thing about it is that you can't really hear it at all while the engine isn't under load. Putting the bike in neutral and revving, and it's barely there — while at moderate speed in second gear and higher, it becomes quite apparent.
This makes it hard to record audio of the noise, because you have to be riding to hear it, and the wind noise overwhelms my camera microphone, even in a jacket pocket.
My guess is that the cam chain needs replacing, or maybe clutch knock? But before I start down that path, I'd like a second opinion.
More relevant details:
* I've just checked and re-done the valves, they're in spec.
* The cam chain is timed correctly with the arrows parallel at TDC.
* The automatic cam chain tensioner has only about half of its distance used up.
* Did the balancer doohickey when I first bought the bike, Eagle mike replacement + torsion spring.
* The rattle isn't coming from the exhaust pipe cover (Already sorted out that one.)
I've already paid $100 to the local shop to check it out — disappointingly, the mechanic said he couldn't hear the noise, but he also didn't try to ride it, so that's not at all surprising.
If this description of the noise makes you think I should try adjusting or investigating something else, I'm all ears.
Here's an audio recording of first revving in neutral, then riding down the block. It's hard to hear over the wind noise, but you can hear the tapping/rattle faintly from about 0:19 to 0:27.