Motorcycle Repair: pw 50, pw 50, two stroke

Question
have an older pw 50 .  1990 or 93. doesent seem to gain speed under the load of a 6 yr old fast enough to make it up inclines. engine idles and seems to excelerate well on the stand but under a load it dosent reach powerband. not even in 100 feet so out of a corner to a jump it wont make it. thank you for your support.

Answer
Kim, There could be numurous conditions that could cause this but the one that sneeks by most is the exhaust gets plugged up or restricted. Because its a two stroke the oily exhaust can build up in the muffler and cause it to lose power. Sometimes it can be removed and hung by a wire then heated with a torch or heat source and the oil will thin out and run out the openings. This usually happen on a lot of the older mopeds as they dont reach an optimum temp in the exhaust pipe.Try this first before buying a new pipe.