I just bought a 00' YZ426F. It came from Arizona & I live in Pueblo Co. I took the carb apart, cleaned it & put it back together. It started extremelly hard, but once it did start it idles smooth & is responsive except for a litttle bog at low RPM. Should I re-jet or do the AP upgrade & see how it likes that first? Its stock on jets & needle clip position. Any help will be greatly appreciated, Thanks. Also elevation is about 4700'