I have an 86 Vulcan 750 that has a hard time starting about half the time, and not always when cold. I cut off the exhaust, which may or may not be the culprit, but putting them back on is not an option. I suspect not enough spark; the plugs are new, but I notice that the right front plug wire has spark jumping from the wire to the spring-wrapped throttle cables occasionally. If I move the wire away from the springs, the spark stops and the idle speed goes up a bit. However, even with a slab of rubber wedged in to keep spark from jumping that gap, it's still intermittently hard to start. I know this is all very vague, but I'm looking for a place to start. Advice?