I just bought an 09 kx 250f aluminum frame with a 04 kx 250 motor (kx250af). I have only rode the bike once up my road for about 5 minutes. When i got back to the garage the brand new back fender was painted black. I know this is common with a two stroke but this is a little extreme. The bike has a brand new top end in it and the oil gas mix is 32:1 which is usually what it should be I think. I also believe the bike is jetted good. It also has a brand new silencer. So what else could be the problem? Any ideas would be much appreciated.