Pipes *new* go anywhere from 350 to over 600, a two stroke engine like any other has to be rebuilt at some time...When the compression gets low and the bike starts to run like crap...Now you can do the matainnece on it such as clean out the air filter regularly, clean out the carbs, have it jetted properly, and run a good premix to go along and this will reduce your vulnerability to blowing it up. Check the compression regulary and keep checking your plugs, if the bike doenst seem to run right, take the time and check all the possiblities-airleak, missing carb screws, ect...Plastics not shure Fullbores get my pic though they are great, check out their website, When you look at it check the rims, the frame, air filter, tie rods, chain, swinger, hubs, look for blemishes on the engine, look for stripped parts...Best bet would to be to test run it. Usually you can change your rings or pistons every season, but I dont as long as the compression is good 115-135 then you are home free, if a little lower take the head off and get new rings , but while the head is off check the pistons, now if your compression is real low then get the whole 9 yrds-Psistons, rings, pin, Gaskets....I know its alot for you and the other shee-rades will add some stuff but I hope you get what you want...Later man