I have a newly dual sported 04 wr450. It was running great up until 1 week ago. No recent changes other than a dual sport kit. Running the same FMF Q for over 6 months. My problem is when i use over 3/4 throttle it gets super loud, pops alot, and no power. It seems to run fine at idle, although getting harder to start. sputters a little up to 1/2 throttle, and sounds like theres no muffler (and no power) at 3/4 and above. where should i start?