I put brand new teflon coated forged pistons in my 340. The instruction sheet for the rings told me to put it in 4th, slow down till 20MPH so its kinda bogged down and give it full throttle till 45MPH. Really you just want a lot of load on the motor but dont beat on it. Its says to do this about 10 times and the rings should be broken in. The motor now has 1600 miles on it and it runs awsome!!! Typically motors take a 500 mile easy break in time.
