I have a Tomtom one that I use and notice that the unit would turn off when running the bike at higher RPM. I could turn it back on but it would shut itself back off in a couple of minutes. I tried it in the car and it works fine. I also have a Gamin Nuvi 250 and it acts the same way. The bike is a new '06 wee with 2,000 miles on the OD. I still can use the GPS's but I have to use them on battery power then allow them to charge up when riding at slower RPM's. Other than the GPS problems the bike runs fine and I have other devices (XM radio) and never have a problem.