I having some problems starting my 99 300ex. When the engines cold it starts right off perfectly. But after riding a little bit and taking like a 5 minute break it doesnt want to fire. It acts like the spark plug is bad but Ive replaced it and that wouldnt make sense since it starts up fine cold. If I hold the start for about 10 seconds it will usually fire up but thats not supposed to happen. Any ideas would be great, thanks