I have a 2002 sportster and i noticed the tach jump to 0 then quickly back to correct speed. A few days later(today) on my way home the headlamp dimmed and the engine kinda stuttered like it was running on 1 cyl. Also the tach jumped to zero, the odometer went blank, turn indicators wouldnt work. Then it would come back for a min then do the same thing on...off. It'll idle fine but as soon as i give it any throttle the odometer fluctuates and the engine stutters.

 

Sounds like a problem with the charging system.

Try to debug using the stickies in the Electrical/Lighting/Alarm section. It's most likely the voltage regulator, but you need to check the stator too.

 

Start simple!


1) check battery terminal is clean and tight and ground wire to frame.
2) Check main fuse, how hot was it outside(overheating)
3) ignition switch, is key tight and doesn't wiggle.


Keep reading the forum, my electra glide 03 was doing the same and it looks like sandwiching the leads on the silver terminal between two nuts on the main breaker may have solved the problem. More metal acting as a heat sink,better air flow, and raising the leads up a bit so it doesn't overheat and trip. Only time will tell. Good luck!

 

02 sportster electrical problems: http://youtu.be/J_o40z1DQQM
I also have a clip uploading to youtube now with a meter on battery.

 

I went out today to do some testing. I started it up and it ran fine. Let it idle for 15 20 mins the voltage stayed the same around 13.3. Took it for a test ride around the block a few times and it ran like nothing happened. Although i did notice from a complete stop, i would take off decently fast and the speedo would accel to 5 10 mph then go off and back on again. But only when taking off fairly quick. Although the speedo acting like i just stated the engine ran perfect unlike last nights stuttering. Also noticed at idle with an indicator turned on the heap lamp would dim when the indicator lamp would illuminate. Makes me think stator also because of the reading im getting when the rpms increase (ill post the video as soon as it uploads to youtube)but the fact that my bike idles and doesnt die nor lose voltage makes me think otherwise.