. I have a 2001 Honda XR650R that has been uncorked, and I suspect it to have very low miles. I am the second owner. The bike starts fine, idles fine, but will not rev over ~ 3500 rpm. It just starts stuttering and coughing and tries to die. Here is a list of everything I have tried.
1. Swapped the carburetor from my brother's XRR, along with cleaning my own numerous times and trying it. The jetting is fine on both as they both use to run great with their own carburetors.
2. Replaced the stator, coil, cdi, and rectifier. I tried each one individually and tested the bike. No change. Also, just replace the spark plug wire and boot. not to mention it has a newer spark plug in it, this was the first thing I replaced when it started acting up.
3. tested for vacuum leaks in the air boot and the intake. no sign of any.
4. just took all of the automatic decompression release garbage off of my cam. the cam chain and the cam chain tensioner all look to be in good shape, keep in mind this is a low hours, low miles scooter.
5. I checked my exhaust to make sure it was clear of any obstructions.
6. I ran it with out the air filter to see if that was the problem.
7. check of the valves numerous times they are spot on.
8. the petcock is operating normally and flows well.
There may be a few things I have tried that I can think of right now. I really don't know what else it could be. If anyone has any input it is greatly appreciated. Thanks in advance.