Sasa

Hello Bikeriders, Since some weeks i got problems with my Radian. During my riding after about 10 miles the power increases suddenly. Its like the bike dont's gets fuel. I checked mij breather hose, the one from the tank, there was no obstruction. Air comes in to the tank(vacuum thing) .This was properly working, then i tride to have a ride with the tankfuelbutton open to see if this is the matter, but yesterday it happend again with -1 degrees below zero(with button open) Does the Radian has a tankfuelbutton that breaths? I know the thing of icing cabs it happens when its cold, but is this possible with the Radian. Are there of you guys who is recognize this problem? Anyway the Radian starts good he rides perfect during the ride, engine speed stationary is 1,35(x1000) very good handling, only the problem what i have. I hope you can help me with some information or what do i have to do else greetz Sasa from Holland