Just bought an 07 420FM. Noticed the exhaust turning a shinny blue color but only three quarters the way up the muffler??? I though the full muffler would change color??? Is this normal??

 

My 06 foreman is doing the same thing .It just turned 38 miles, so id say its normal.?.?

 

Blue pipes usually mean a lean condition causing the exhaust gases to be extremely hot. I would check and make sure that you aren't about to grenade your motor.

Stick your finger in the exhaust pipe (while cool!!!) and see if it comes out very clean or with just a little bit of black. If it is very very clean you're running lean and need to jet it a little richer.

 

The discoloring is normal, and lots of idleing makes it worse. These are air cooled motors, and need a flow or air accross the motor to carry away the excess heat. This, along with making the exhaust header out of thinner gauge material, leads to discoloring.
Its posible the jetting is a bit lean, but if its totally stock ( no after market air filters, or pipes, and the air box lid is still on), i wouldnt be too concerned unless you have other symptoms.

 

Absolutely nothing abnormal. I never had a pipe in all these years that didn't tune blue. If it is only partial at this point, I would be the whole thing will turn in time.