I recently tried to upgrade my exhaust to expansion poo poo pipe. I am experiencing extreme sluggishness with new pipe. I'm wondering why effects are opposite what I desired and expected. New pipe is 24" to expansion then muffler. Intake has a 7" manifold with a couple bends. Motor runs good, 30mph flats, with short stock pipe. Have jets for my nt carb but moving up to larger jets only makes it run worse, running 65 now. Also if I take off the air filter it runs like crap, seems rich, can more air flow through carb make engine run richer? Have replace intake and exhaust gaskets, port matched, checked float height, cleaned carb, plug chop, new plug, removed fuel filter, hmm. Any ideas? Is my intake too long? Should I get a better carb? Looking at some keihins, but seems like overkill on a little China girl.