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Possibly premature fuel ignition? It only happening when your motor is hot also points to this. What octane fuel are you using over there? Make sure your sparks aren't misfiring and maybe try an octane booster. Higher octane is more resistant to premature ignition. You also mentioned getting the CCT replaced. You're sure it was done properly and the timing didn't get disturbed?
Read thisAGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - What Is Pinging, Detonation and Pre-ignition
Randy, what noise did the loose oil pump chain sound like? Did you save an audio of that?
Goodmango- the oil pump chain runs down attached to the water pump shaft, just back behind the clutch. Could it be coming from that area? There is no adjustment for it, as it wears, it flops around. I thought I heard a deeper, knock at one or two points, is that the noise or is it the lighter ("Baseball cards in the spokes" ) kind of sound?
Probably not related as I relistened to it, also Goodmango, when you changed out the CCT several things:
Did you notice any difference, was that sound there before and obviously after?
Did you happen to check how far out the NEW CCT stuck out from the block when fully extended? (I'm trying to see if your cam chain may be stretched, nw rattling around in the cases).
Below pic is my old KLR, with the CCT fully extended, with the new chain in. You can see how much room it NOW has (had) with the new chain. Before it was almost to the block (as the chain was so stretched and rear guide worn.)
I don't know. It'd have to be WAAAAAAAAAY loose to hear it. Chains are pretty happy when loose as long as they don't skip or hit anything! When too tight they don't circulate lube and the pins snap. I'd say its NOT a chain issue neither the cam or oil pump. Something else!
If i had to guess I'd say its not a rod or the upper end. Also because it does while not under load that removes the bad fuel from the equation. Unless its REAL bad fuel but it doesn't sound like spark knock to me.
It sounds like its behind the engine because the sound is NOT 1:1 with engine speed. Its reduced and lagging behind engine speed and is somewhat load dependent (accel and decel).
So my question is this:
How different is it cold to hot?
What OIL is in it?
Does it get LOTs louder as the load is increased - i.e. like 4th gear at steady state vs other gears. Pick one.
Does engine braking make the same amount of sound as accelerating in gear X?
If i had to guess I'd say its not a rod or the upper end. Also because it does while not under load that removes the bad fuel from the equation. Unless its REAL bad fuel but it doesn't sound like spark knock to me.
It came to mind, and an octane booster just seemed like a cheap/easy way to rule that out.I'm not completely sure about the octane here. (everything in Korea is confusing) but I did try premium last fill up and no improvements. My mechanic put in a new Yamaha CCT I hope he did it right. The sound existed before and after the replacement though...
Not necessarily bad fuel or spark knock, but premature fuel ignition due to too low of an octane is what I was getting at. Hot spots in the cylinders may cause premature ignition, and higher octane is more resistant to igniting prematurely. This is my understanding. Not trying to argue as you are much more knowledgeable than me in mechanics. Just trying to throw ideas or there
It came to mind, and an octane booster just seemed like a cheap/easy way to rule that out.
The sound does seem to be coming from that area behind the clutch. Its where the black hose from the radiator runs to. I'm not sure how sure how far the cct extended sorry.
Oh really? My mechanic used the stethoscope so I thought that was better. I'll hunt down some wood and run that test and report back asap. May take me a day as real wood dowel isn't that easy to find in Korea haha. Thanks!Have you placed a wooden dowel up this engine and listened to it yourself? It's very different that what stethoscope shoves into your ear. Try it and report back.
Have you placed a wooden dowel up this engine and listened to it yourself? It's very different that what stethoscope shoves into your ear. Try it and report back.
Loose cam chain rubbing up against the PU sensor like "Vegas's" bike??? (I believe it was his bike)
How many miles on your bike?
Just over 20,000km so about 12,500 miles...