Engine noise, what could cause it?

I have been hearing a little knocking noise while riding under power (half throttle +) coming from the engine. It's more of a ting rather than a knock. I've checked the valves and they were perfect, cam chain was tightened a tad, and oil was just replaced. Anyone have any idea what else it could be?

My only thought would be if the PO replaced the cams and I should be running a higher octane, which I highly doubt. They seem to have been playing with it a little, but never used the correct wrench size on anything so I'm not too sure they knew what they were doing.

I'd check the countershaft(engine ) sprocket for tightness, and while your in there, clean and re-lube the clutch mechanism throw out, & clean off any chain lube from the clutch push rod. I've found some paint thinner on a rag or paper towel, to be the best solvent for chain lube.

Bet a dollar to a donut it's an exhaust leak

MF - I'll look into that, I just lubed up the chain with a silicon chain lube

Steell - I just replaced the exhaust gaskets but the bolts were pretty worn down and I didn't feel comfortable torquing them down just yet, so I ordered new ones and I'll see if that fixes it when they come in. Thanks!

I would fill up the tank with 93 octane and see if the problem goes away. Back when the bike was made the cheapest gas was high octane compared to today. Ed

650ed, I put in half a tank of 93 octane and the noise still persisted. I'm going to run this tank empty and see if the noise is still there. It still sounds like its top end, left side noise, but I don't have a stethoscope to confirm exact location. Any other ideas?

Just get a length of hose, up to your ear & start probing the areas you think the noise is coming from, with the other end
Pete

Hey guys, I changed out the ignition and adjusted it per manufacturer specs. That seemed to make a little difference and the bike ran a little smoother, BUT now it's even louder! I took a video of it and it's linked here. Please note when I try to give it a ton of gas, it just hits 6k rpm, makes some funny noises but wont go past that point. I tried adjusting the fuel air from anywhere between 1 turn out, to 2 turns out, and it made no difference on the throttle being limited to 6k rpm. I took temps of the engine, right next to the spark plug, and they were at 230 F. Also note that the imbalance between the two exhausts is now fixed with the new ignition installed.

Whens the last time you adjusted the cam chain?

I don't think your noise is rod knock by the way.

I adjusted the cam chain per the service manual last week, when I started hearing the noise.

Here's how I adjusted it, in case I did it wrong somehow. I took off the cap to the adjuster, rotated the crankshaft until the little rod in the center of the adjuster was furthest inward. Then I tightened down the nut to be a hair out from flush with that rod, then replaced the cap. That's what the manual says to do, so I did that.

I don't think the 400/440 twin was all that quite to start with if I remember them right.