I just replaced my speedometer under warranty. So as I am looking at the speedo in my hand, I decided to try and figure out how to get the speedo more accurate. Basically there are three ways to recalibrate this type of speedo. One, demagnetize the drive magnet. Two, move the cup away from the drive magnet. Three, stiffen up the little spring that returns the needle to zero. Here is a good article that explains all this. LINK

So I decided to try to stiffen up the spring. I moved the little tab that holds the end of the spring up and to the left (in the pictures). Not very much. When you move it, you can see the spring tighten up. I put it back together and tested it. I now have a speedo that is dead-on until 40 mph indicated. It is 1 1/2 mph off at 55 mph indicated. And at 70+ mph indicated, it is off 2 1/2 mph. It is close enough for me that I don't think I am going to take it back apart to get it any closer to the gps.

Of course, try this at your own risk. The tab is very easy to see when you are holding the speedo in your hand. It was hard to get a good picture with my camera. The nice thing is, the tab moves very easy and goes back fine if you move it too much.

I am pointing at it here, but it is a little fuzzy.

Not as fuzzy.


The only down-side to doing this... now the bike is not as fast. []

 

what happened to it that u had to replace it?

 

All the numbers on the trip odometer stuck together and rotated together so I couldn't reset it anymore.

 

So from your picture, how far and in what direction did you bend the tab?

 

I bent it to the left as I twisted it clock-wise. I moved it maybe .02-.03 of an inch. Not very much. As you are doing it, you can see the spring wind tighter. I could feel the difference/ tension, between stock and tweeked, when I moved the speedo needle with my finger. It is actually harder to explain than to actually do it. I can't tell if this is making any sense.[sm=smiley29.gif]