Today my 04 yz450f died multiple times doing exactly the same thing. Rode trails, hill climbs, technical, and some faster sections, no problems, runs great. Get down to the main dirt road open it up, cruising in 4th dies after about 3-5 minutes, every time. The bike accelerates fine otherwise, no hesitation, does everything I ask of it. When it dies it's like hitting the kill switch. Won't restart for about 5 minutes, at all. I read some other threads about similar issues. Ideas where to start? electrical, fuel issue, carb issue, vapor lock? Thanks in advance for any help.