Hia guys,
My Sportster is a 1996 1200, its my first Harley. Its my test machine, I'm hoping to come over from Scotland and do Route66 on a hire bike with Eaglerider. I've only had it a couple of weeks and its given me grief! You guys have helped me with my electrical brake and indicator problems.
So if I can play on your good nature, can you give me any tips to solve an erratic speedo. It zero when the engine is off but waverers all over the place when engine is running.
Thanks,
HaggisHead

 

It's likely a bad or dirty VSS (vehicle speed sensor). You can remove it and try cleaning it, or replace it.

 

Hia Mate,
Thanks for response, please be gentle with me!! this is my first Harley...two weeks in my ownership. I own two Triumphs 1966 Bonneville and 67 Tiger so I'm used to old time electrics. Where is the item you described and how do I repair it?
Thank you,
HaggisHead

 

It is located next to the starter motor and is held on with a allen bolt. when you pull it out of the case just wipe it down and try your bike if it is still doing the same you will need to replace it. same removal process but follow the wires up to the disconect and disconnect than add the new one. they are around $60US to buy new on ebay.