I have a 1995(?) Yamaha Waveraider 700. Last year we had a few times when at full throttle and it would bog down and die. It'd start back up and away we'd go. This year we ran about 2 tanks of fuel through it and it ran great. Then it started bogging all the time. It will start and idle all day. When you hit the throttle it bogs down and dies. Sometimes you'll think its going to take fuel and go but again it dies. Start right back up and idles fine. I have replaced plugs, replaced fuel pump, replaced fuel pump and cleaned carburetors. I have checked compression on both cylinders and have 145-150lbs. The only thing I haven't done is replace fuel lines. I feel sure the fuel pump is working because I get fuel out of the return line to the tank when its running. Any ideas????? The boys are bummed out.