Pinging?

What exactly is pinging? Is it kind of like the pre-ignition sound that cars can make if they have too low an octane or their timing is off?

I have a 91 CR250 that makes a sound when I'm really on it... usually at high speeds in the higher gears and when I'm on the throttle. I'm not sure if it is the infamous "pinging" or what but the bike has no loss of power. The sound however does bother me as I don't really know what the cause is. To me it kind of sounds like a ticking sound but at such a high frequency it almost sounds like... I actually don't know how to describe it but it may be what others are terming as "pinging".

Anyhoo... any suggestions as what to check, what to do, or how much I should worry about the sound? It does seem to be eminating from the cylinder somewhere but it's hard to tell because I have to be going faast to hear it and trying to tell exactly where it's coming from is difficult. I like things to be in good mechanical order so I would like to figure out what it is.

Thanks for any and all advice.

Richenening...

Gonzo thanks for the replies.

I'm pretty mechanically inclined but that does not include carbs. If I remember correctly the terms richen and lean are in reference to the amount of fuel relative to the amount of air... is that correct? So does that mean I need to have more fuel per the same amount of air (i.e. do not increase air flow only fuel)?

Is the needle the control for that or do other jets need to be adjusted? I would appreciate any further advice.

Thanks again.