New to this forum. Myself and my buddy have the same problem with our 450es's. Mine is a 99 and his a 00.
We both have pinging problems when at low or no load conditions. We have tried different gas, and plug heat ranges. Typical example would be riding down a road in 5th with the motor pinging. If gas is applied pinging subsides or if perhaps the road starts to incline up pinging subsides. Mine has been doing this since new and the dealer/dealers say they have never head of this. No apparent damage as I am near 3000KM on the odo. Other that this it has run flawlessly. Both units are bone stock.

 

You say you've tried different gas in them???.Are you talking name brands, or higher octane??? Try running 92 or higher and see if that help...I have a 400EX and it's required in mine or it can cause pinging so that's what I run...If that doesn't help, then I don't know what else to tell you. I know on autos, it's usually that the timing needs adjusted., but I'm not sure how these things work.....I've never had to work on a quad motor other than changing the oil......Good luck......

 

Good thoughts but since it doesnt ping under load I would have to rule out octane/compression problems.

I wouldnt be suprised if it was something to do with the auto set up since it doesnt make the sounds when under load. Some bearings are known to be "noisy" when running free also so thats allways a possibility.

then again if there isnt any problems I dont think I would give it much worry and if there is an unknown problem once it breaks you will have less trouble finding the cause [img]i/expressions/face-icon-small-smile.gif[/img]

 

Bring it in to get the valve lash adjusted first. That's your most likely problem.

 

I forgot to mention that I have adjusted valves 3 times since new. The gas I tried was different brands and octanes.

 

you may be lean at part throtle try adjusting the air screw or move the clip on the needle down one notch
I have seen 450's run bad with just a k&n filter[lean]