You could try removing and cleaning the vss on the tranny. Every Harley I’ve ever ridden ( more than a hundred) underread by 5%,
So now you know why so many vehicles want to run you over on your Slow Harley.
I fit a Healtech Speedohealer on my personal Bikes. Easy to fit and program @$ 80.

 

Every HD I've owned came in about 5 mph under real speed, at 50 and up, after you know that, just ride it at the 5 mph over the speedometer read out

 

Just thinking: Higher mileage on odometer equals less money at trade in or sell time because speedo is reading higher than actual mph.

 

Powervision has the ability to adjust the speedo output.

When I got The Powervision from FM it came with a map loaded and a new number for the speedo. Mine is now right on the money.

I hope this helps.

 

Now this thread is twice as good as you thought it would be

 

Can you remove the VSS without removing the starter? Maybe cutting down an Allen key to a lower profile

 

mine reads 5-7 mph off at 70. even still, i find myself passing more people than pass me when i'm doing +3 indicated over the speed limit. i go with the logic that my speedo is 'pretty close' and ride as if it is. i've found that in my older years, a couple mph is not gonna get you where you are going that much quicker. if you want to make a big impact on your time of arrival, you're gonna have to do substantially more than the speed limit. and that comes with all kinds of problems that i just don't want to deal with.

never had a speeding ticket on my bike.

 

Different tires will make a difference in speedometer accuracy. My 2007 ran about 5 kph off until I changed the wore Dunlop to a new Michelin Commander II. With the new tire it was correct with my GPS

 

I’ve got to wonder…would wear of the tire….and perhaps brand of the tire… and perhaps inflation of the tire make a difference. It seems that all would have the possibility of changing the circumference some which would in turn change the reading of the speedometer.

 

yes, it would.