I’ve got a 2002 XR650R with an FMF Hi-Flo header and Q2 exhaust. My jetting is: 175 main B53E 3rd clip 68s pilot 4000 ft riding elevation. When I reach 4000 rpm or so the bike sputters and loses power. I’ve gauged this around 4000-5000 rpm, but I think it starts to do it worst around 4500. It does this with half throttle or wide open throttle, so I’m not sure it’s a jetting issue. Otherwise the bike runs great at all other RPMs, even higher RPMs. I’m wondering if it could be an ignition thing, but not sure if this makes sense? Any advice?