anyone have experience with riding at altitude. Went for a lengthy ride yesterday started out at 7500feet, then headed up the mountain, we were going for treeline up around 11-11500feet. at about 10,500 feet my fuel pump must have stopped working because I was starving for fuel. I couldnt keep it started. I let it sit for a while and could get it started but the fuel pump would not stay going. I would turn it off and then turn it on the pump would not run. I checked the "O" ring on the fuel quick disconnect and it looked fine, and I let it sit to see if maybe it was getting vapor lock. But everytime I turned it on there was no gas in the fuel filter, Finally it would run a few times and I would get it started and headed down the mountain, as I got farther down it worked like normal again. I thought with fuel injection altitude didnt make a difference?? anythoughts? It made me upset i didnt get to go to the top with the z400 the raptor nad the two 250r's. And when the pump did run..it sounded funny.
thoughts?
thanks
graham

 

I could be wrong but I am pretty sure one of the ways altitude is compensated for is by changing fuel pressure at the regulator at higher altitude it would need to be leaner less pressure pump would be fighting this tighter regulation.I will check this out but I would say your fuel pump is weak.