I have a 21 3 port R that has around 3 gallons on it, the motor has been broken in the way Go-Tech recomended. My question to you guys is this....
Can I rebuild this engine with a 5 port sleeve and con rod or does it have to remain a 3 port? I was hoping to get more life out of it but that's nitro racing.
By the way, the 3 port had a ton of power.