Jims65CA77 wrote:…. However... the speed it shows is slower than I am going, which makes me wonder if there isn't some "crud" in the bottom of that "dish". Good news is, the Odometer is working fine for the distance I travel. The speed isn't too much of a concern as I only ride it around the neighborhood anyway and rarely go over 40 mph.
You can calibrate the speedo if you want to have it read correctly.
Here are the steps:
Steps:
1. Ride bike at constant speed (I used 50MPH) and check actual speed vs GPS or other known correctly calibrated speedo riding with you.
(I used a hand held GPS zip tied to the steering damper
2. Note the difference. (When my speedo said 40MPH, my GPS indicated 50 MPH actual)..10 MPH off!
3. Dissamble the speedo.
4. Connect the bottom end of the speedo cable to a reversable drill, run the drill wide open (in reverse) and note the indicated speed on the speedo. (my speedo indicated 38 MPH with the drill running wide open)
5. Rotate the tab on the needle spring stop to either increase or decrease the tension on the spring.
(since mine was reading low, I needed to decrease the spring tension)
6. Re-run the drill and see if the new max reading on the speedo is increased (or decreased) by the same amount as the original error. (My error was 10 MPH, so the new drill max reading should be 48MPH on the speedo instead of 38MPH.) This is a trial and error process.
7. Repeat 5 and 6 if necessary.
8. Reassemble and reinstall the speedo.
When I rechecked the bike on the road against the GPS, it was dead on the money.
Note that when choosing a "correct" speedometer to check against to begin with, the speedometer on most cars and motorcycles are at least 5 to 7 MPH off at 60 MPH even when new, so GPS is best to use.
