Is it possible to adjust the speedometer?

[jhh925]

FIXED! Replacing R14 with a potentiometer, then tuning the pot on the road while using a GPS speedo on my phone did the trick. A few observations:
- I used a super-cheap 5-100 ohm pot. I got it wo within 1-3 mph. I'm happy with that.
- Using a GPS speedo means that you need to let the GPS settle down before you have a number to compare to. The GPS didn't seem to react to speed changes very well, so if you want to double check at 30 mph, you need to find a nice open area where you can to 30 mph for a bit
- The speed o is VERY sensitive to any attempt to adjust the pot. Every time I started to tweak the potentiometer, the needle would jump around. I assume there's a good deal of noise in the pot. And I guess that's fine because the car speedo settles down when you leave the pot alone. Just makes it a bit tricky on the road.

Pics or it didn't happen

Yeah, well, the issue is that the GPS speedo is on my phone, so I can't get the phone & the speedo in the same pic. Sorry.