Bike is a 2007 Ultima Fat Bastard 250 (kit bike) which is based on 93-99 FXST. Carbeurated 113 ci Ultima and 6 spd trans. Was cruising down the interstate at 75 mph when she started sputtering and would bog under throttle. Reached down and switched to RES cause I thought that might be the problem. That didn't help so I limped the bike to a rest stop which was about a half mile up the road. When I parked, it was idling fine but as soon as I gave it throttle it would bog and sputter. I shut the bike off and went to restart it, and nothing...No lights, no nothing. Wondering if anyone has any ideas of what it could be?

I already know I now have to replace the battery because it is only showing 10.5 volts after being on a tender for 2 days.

Mechanical linkage to the throttle is fine and the slide operates normally.

 

Sounds like the alternator or regulator went out and over charged the battery. Try a new battery to see if it starts and if it does check to see if it's getting charged too much. If you have over about 14.8 volts at the battery when the bikes running then it's overcharging, if it's under about 11 volts then it's in the charging system. It could also just be a battery cell went bad. Hope this helps.

 

Sounds like a good place to start, thanks!

 

Replaced the battery and she fired right up!! Went ahead and did all the charging system checks just to be sure. Looks like it was just the battery this time.