My 05 drz400s pops pretty bad while coasting downhill. I cant remember what my jetting specs are but i have the yosh rs3 exhaust, 3x3, and k&n air filter. Is there anyway to check to make sure my header isnt leaking? I have my suspicion that it could be the problem but it seems to pop even when normal riding when i let off the throttle. I ride from 500-3000 feet elevation normally between 50-90 degrees. The bike runs good but seems like it could run better and the popping is starting to get annoying. Should i check my valves? The specs i can remember about my jetting is dynojet kit 3109 i believe the needle is on the 4th clip, 145 main, 25 pilot, and the shim that came with the pipe. I could be wrong but i think thats what there at. thanks for your help..