New WR426 strictly stock except for the W.B. E-series pipe. The pipe improved the perfomance considerably when the weather was warmer in the 60's. Seemed to me that it was running great. I'm at approx 5500'elevation. Now that the temperature has dropped,(now in the 40's or below)the motor is crapping out when I accelerate off the bottom. I'm wondering if anyone has experienced this and could suggest specific adjustments. I guess I'm a little timid of the complexity of these carberators and want to be pointed in the right direction from the start. Also any other things that might unleash more performance. I'm finding a great deal of info from this website and just want to say I'm really enjoying the entries you all have posted. Thanx Again !