I have friend with a 2000 FX softail with a carb, when cold runs perfect when hot after 1-5 miles it will miss, won't pick up speed. The speedo goes to zero, odometer blanks out, lights go dim. If you stop and let it sit for 5 minutes it will start and run great for less than a mile then do it all over again. The speed sensor, ing module, ing swtich, have all been replaced. the charging system is good 14.4 v when it is haveing the problem, cleaned the grounds, voltage dropped the battery cables and wires from the ing swtich all good. I took the handle bar swtiches apart checked the wires for the stop swtich. Any other ideas? One question I have is could the cam sensor short and take out the speed sensor and create this concern?

 

I believe the bike has a crank shaft position sensor not a cam sensor. It is possible that if the sensor is not working properly, it will run like crap when hot. Take the sensor out and examine it. It may have build up on it. Those wires may be corroded. Also, check all the ground wires associated to the spedo and lights.