anybody else had this noise

trailer01

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Does anybody elses 650 make a metallic rattle sound or knock when you put the engine under load at highway speeds, does not do it a slow speeds, engine is pretty quite at first start up, than valves rattle slighly when hot, has made that noise ever since i had it, even replaced the cam chain and head gasket a few years back and when i had the head off there was hardly any ring ridges in the cylinder. any way i was just wondering .

sounds more like a rattle to me though.

it runs great and I get about 60 miles to a gallon of gas.
 
I think you're running too lean and the motor is pinging when you put a load on it. 60 MPG is very, very good gas mileage, almost too good.
 
What year bike do you have? What kind of ignition do you have? If you have points or some type of cam driven ignition you may want to take a look and see what your full advance timing is. It could be advancing too far and need to be retarded just a touch to get it back in spec.
 
How do you check to see if it is running too lean?

engine itself has close to 40000 miles on it.

I have tried premium gas still the same.

Thanks
 
Your ignition could be advancing too far. You could be running too lean. The spark plug heat range could be too hot. The octane of the fuel could be too low. You are in too tall a gear for the load you are pulling. From your description, it sounds like pinging, pinging is the onset of detonation. Detonation can and will destroy the engine.
 
it seems the noise gets it little loader when the engine has been running for awhile.
at first i thought it might be piston slap,or something related to that, but coasting or when its cold you can not hear it.
 
I checked plugs the outside edge of plug is black the electrode is still white just replaced them a 1000 miles ago and bottom of plug the curved part is whiter in color on both plugs.
 
What plug are you running. What pipes air fiilters. What has been done to the carbs.
Could be carboned up I suppose, bumping compression.
 
Glad you brought this up I will be pulling my plugs tomorrow. If they look like yours I will be moving the needle up a notch. If I wasnt so lazy I would have taken it to my friends shop and tuned it on his dyno
 
I used the standard air filters, champion spark plugs, I checked cam tension it is just about even with the bolt.
 
it also has standard pipes and all i did with the carbs was cleaned them did not change any setting.
 
someday i would like to do a complete top end rebuild with new pistons and everything, but even when i replaced the cam chain guides and chain a few years back due to a leaking headgasket, the noise was still there, maybe i should wear earplugs lol.

just a slight acceleration will make the noise worse
 
My 79 is making the same noise, louder at part throttle acceleration.. Some of it might just be the larger carb opening letting more intake noise out? I want to check my full advance timing yet. (I have points) I have one valve still sounding a little loose. Cam chain adjustment done while idling, slowly tighten till the plunger isn't moving as much, back off slightly. I also have after market mufflers and larger pods. I will see what happens when I put the stock mufflers and air cleaners back on it.
 
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