I'm having a pinging problem, and I have heard/read/been told that the squish clearance is way off on these bikes (talking about 02 CR250 here), and that milling the head down is a common fix. Anyways, I went ahead and did a squish test a while back, and the thing really was WACK! So, would gettin the head milled down be good idea? Checked jetting and the motor is fresh with about 3 hours on it. Blows hard and is a tight motor. How much should be milled off? .01? No leaks in the motor either, all seals are good.