My 2006 Yamaha YZ250 has stock jetting, lower gearing and a Pro Circuit pipe, but it pings under a load. What is the solution?
You have two simple solutions: (1) Add a small amount of race gas to your
pump gas (which you must be running since your YZ250 is pinging). Don't
run 100 percent race gas, just add one gallon of VP Racing C12 to four
gallons of pump gas. That should fix your pinging problems. (2) Even
cheaper, you can change the stock N3EJ needle for N3EW (the N3EW needle
is richer on the straight portion of the needle). The N3EW came
stock in the 2007 Yamaha YZ250 (and all subsequent YZ250s).