I am getting my 1997 Polaris 400cc sport totally rebuilt top and bottom, My question is when I get it back on How long before I can drive wide open, and run it like I want to. Is there any certain things that I need to do before riding the first time, or is there anything I should avoid doing on my 400 until it is broke in.
Thanks

 

Once you go through your first tank of pre-mix gas then you are good to go. The one thing with 2 strokes is you need to warm it up before you ride and when it is new ride it like you stole it. It will be faster in the long run. If you putt around when it is new it will not loosen up. So it will be slower and tighter. Warm it up, run it hard but dont ride with throttle wide open. It is ok to get on it hard to loosen it up. Just dont open it up for a long period of time.

 

be sure the cooling system and coolant bleeding is done alright,let it warm up and check for coolant leak and air leak,then if you didn't add any mods run the same jetting,you can WOT,but not for long,varying the throttle positions alot,be sure engine is not overheating,let the motor cool down after each speed run.
it take some tank of gas (4-5),but the most important thing to avoid is:lean mixtures and overheating temp.that will determine your new engine's performances in the future.