Nah I have no place to put a gps and im not looking to be dead nutz just withing a few MPH like most bikes. I've had the same results, around 10 mpg with all the guys I ride with and my wife in the truck, so good enough for me to know its off.

I looked on the speedo and it does have the ratio on it, 2240:60. Guess I just need to get the correct drive for that and see if it helps.

 

The 2240-60 is for 16" wheels.
If you're gonna change wheel size you need to research what you need for that particular wheel.

The possibility exists that since the speedo is made in China your problem could be internal to the speedo.
I haven't had much luck with replacement parts from that part of the world.

 

Softails with 21" front tires use it also...due to the height of the sidewall the overall height of the two tires is not that different...having the wrong drive on it will make a big difference.

 

Which bikes use the 2-1 or the 1-1?

 

The older FL's, 1:1 are tranny drive, and 2:1 are either tranny and or some front wheel drive.)

 

Just for fun I went out and measured each.
The 21" wheel is 3/4" taller than the 16" wheel (give or take a smidge).

 

Which bikes use the 2-1 front wheel drive unit?

 

My '83 FXRT did, as did most front wheel drive bikes from '73 or so to '90 (?)

 

They used the 2:1 ratio all the way back to 37 I believe...the front wheel drive units came about in the 70's...and they used them on some models(XL's FXD's FXR's) till they changed to electric speedos in the mid 90's.

 

The only thing stamped in the bottom of my Oem speed o meter is "MADE IN JAPAN"...
But there is a red ink smudge that I can't read....