ts250 - new cdi control module
The bike won't go over 6K RPM, which corresponds to about 63 MPH. It surges at that speed. It really feels like the ignition just stops firing. I had previously replace the plug and wire, the ignition coil, and the pulser coils. None of that worked. That left only one ignition part, the cdi control box. Unbelievably I found a place selling a brand new aftermarket box. It was expensive ($175) but I figured it was worth it to have full speed again.
It installed easily. Unfortunately it made absolutely no difference. The bike still won't go over 6K RPM. What the heck? Not only have I replaced all the ignition components, but indirectly all the wiring and connectors too.
The bike maintains 14.2-15 volts while driving. The voltage is good, and yet it still surges at 6K and stops accelerating. I don't detect any pinging. I have even filled the tank with 100 octane Sunoco race gas to ensure there is no predetination.
Apparently the problem isn't in the ignition system, but I am out of ideas. I used to be able to do 78 MPH with this thing. Being stuck at 63 MPH makes my commute a little sketchy.