usually ping happens when you are accelerating at lower rpms up a hill (doesn't have to be a big hill) not so much if you are just cruising down the road...also a slight ping on occasion is not a bad thing, it just shows that your bike is tuned just on the edge of being too lean, but not too lean to do damage, which means it is running its most efficent...the fuel additives will turn your plugs brown/orange and also if you use them regularly cause a build up in the cylinders, which in turn can make you ping more...I try and stay away from that stuff, in the long run it can cause you more issues than its worth...you could prolly use a tune, to make it have more power and run cooler, but you will probably loose some gas milage in return (depending on how you drive it)...As, boondock saint said, it may just be something rattling, so i would give the bike a good once over grabbing all the parts that might touch and giving them a good shake to see if they move enough to touch...Once my front fork deflecter on the left fork had a crack at the mounting bolt and started to rattle, drove me crazy trying to figure out where it was coming from....Back, to your ping (if that is what it really is) ..I don't know how many miles you have of even what year it is, but if the milage is over say 15k and you don't do any long trips to speak of or the milage is over 40k you might be getting carbon build up on the pistons, heads etc., to help remove it, you can pull the plugs (when motor cold) preferably when you aren't going to ride it for 12 hours or so.....and squirt into the cylinders though the plug holes about 2-3 tablespoons of automatic transmission fluid, put a rag over the holes and hold it in place while someone cranks the motor for about 2-3 revolutions...leave the rags over the spark plug holes, and let the bike set for the night....the next day, crank the bike again a few times with the raps over the plug holes to blow out the excess ATF, replace the plugs and start it up (outside).. A huge cloud of smoke will come out of the exhaust and when it clears take the bike for a long ride...ATF has a ton of detergents in it that will dissolve carbon deposits from engine parts and leave a nice oily residue ( unlike carb cleaner, brakclean etc.) ....you my find that by getting some of the carbon off the insides of the motor that it will lower the compression enough to stop the pinging.....

 

Just a side note on octane boosters.

I've run most of what's available out there, and all but one does in fact turn your plugs orange and may contribute to upper cylinder deposits.

Amsoil makes a motorcycle sized octane booster. I keep some in my saddlebag in case I get stuck in a place without decent fuel. I have used almost a case of it over the past year and I see no evidence of orange on the plugs, or excessive carbon deposits. It's reasonably priced as well. 1 bottle will treat one tank of fuel.