Gentlemen; I have an 07 Roadglide with 73K miles. I purchased it new and have recently made the change to thunder header slip ons and a SE aircleaner. I had a Stage one down load shortly thereafter. Other than that the bike is stock and well cared for. Recently a problem arose that confounds me. I was riding this summer and after visiting a store I returned to the bike and it cranked but refused to fire. I made several attempts in the next twenty minutes and it finally fired off. This same scenario occurred on one subsequent occasion but the many rides in between were problem free. The Dealer shrugged his shoulders and gave me the deer in the headlights stare. Last night I was leaving a stop light under normal acceleration and the bike acted as if I had hit the "Stop Engine " switch. Over the next twenty minutes it would crank but not fire. I went for a trailer and upon returning in thirty minutes it would crank but not fire, but I did smell fuel. A twenty minute trailer ride home and upon arrival it fired right off and ran well. I'm baffled, anybody have any ideas? By the way the speedo check revealed DTC error codes indicating front and rear cylinder " no combustion".