Moped Army

So, I finally got low rise 'bars' on my moped. It's just a simple plumbing 7/8" pipe. Works, and looks great. A few issues happened though. The On/Off engine switch stopped working, but I fixed that by popping it open and making sure the wires made contact. Fixed. Next issue is that the speedometer has a problem. When I start going, it gets to 15MPH(on the speedo) and just stops there and jumps around, while I'm still actually going a lot faster. I made sure the cable was tight and attatched good. Is there anything I can do? Or, to avoid replacing it, should I just assume I'm going 25MPH-35MPH and not really worry about it.



-Keith