need some help with an engine

[mrriggs]

I got a virgin XS400 that had the same problem. Even with bone stock engine, air filters, mufflers, and carbs that looked like brand new inside and out. Simply went up one size on the pilot jets and the thing ran like a top. I assume the new gas was to blame. I was talking to a guy who said that he tested the gas all up and down the I5 corridor and it was closer to 20% ethanol than the advertized 10%.

 

[tor_bjorn]

Quick question : found this looking for spark plug solutions.

The Autolite 63s are still resistor plugs (correct?). While the BP7ES are not resistor (which I am looking for as well). Why are they interchangeable if at all?