Lots of threads on this. Go with Barons for a better quality.

 

Or just install a speedo-healer

 

Once I put on a 180/65 16 Michelin Commander II, the speedometer was a lot more accurate. If I remember correctly it was only 2 mph at 60.

 

Try this. the down side I guess is that the odometer reads slow. I set mine at 5.0 percent with stock tire, and have it at 3.0% with the 205/60/16 CT. Was dead on with the stock tire and now I'm good up to around 70mph indicated is 69mph.
http://shop.12oclocklabs.com/index.php?route=product/product&product_id=59

 

my F-150 is off ~+15%, have to register 130kph to get 110kph actual.
my 2011 VV is off too, but not so much. I like it reading 120kph knowing it's actually slower.
feel like a rebel (by the speedo reading) LOL.

 

I did research on this last year, there are no alternate pulleys for the 1700. As mentioned the simple fix is with a speedo healer which will allow you to alter the signal to the speedo.

RACNRAY

 

Larger diameter rear tire. Corrects speedo, and improves cornering clearance.

Incorrect speedo doesn't bother me. Just like my wife having the clocks set a little ahead. I just adjust in my head.

I think most vehicles out there have incorrect speedos. My little roadster is showing slower than I am actually going. I like it because when I am hauling around the curves my wife looks over and thinks I am just going a little over the limit.

 

I tried a SpeedoHealer on my Voyager. Had issues with the way it ran. Stumbled. Accelerated poorly. Not sure but I believe the speed sensor input has an affect on fuel delivery and the SpeedoHealer messed with that. Took it off and it ran fine. I'll change the rear tire size to get it closer.

 

Which I had seen this post 6 months ago. After reading this yestarday, I unhooked mine. Road to and from work and its like a different bike now, runs much better. Refer to link below for my thread about issue I was having.
http://www.vulcanforums.com/forums/showthread.php?t=142441