My bike: '97 KLR 250, 11k miles (although my question is not about this bike in particular). My story: Had the carbs cleaned by a friend since the mere thought of opening one up makes me face my own limitations as a man. He told me it was pretty dirty, probably never cleaned before this. Only other change was swapping out the stock exhaust for one the P.O. gave me w/ the bike as an extra. Comparing the two, the one on the bike now is much lighter and looks better as it has no rust. Thus the swap, so I can clean up and re-paint the stock pipe. Bike sounded great, more of a "thump-thump" sound in place of the stock "puff-puff". My question: How does the exhaust set up influence engine output? Seems as though the power band on my bike flattened out and lost a bit of "get up & go". I was surprised since the carbs had been cleaned out, I expected a little more kick as it had been stumbling though the 5-7k rpm range. The engine definitely runs smoother, just seems flat as it throttles up. As I am a self-proclaimed non-genius I throw this open to general interpretation, gentle heckling, slight sarcasm and any insightful banter.