Adjusting the speedometer

[MotoZiggy]

Im going to be changing out my rear sprocket soon. I noticed on my service manual CD that I just got ($0.79 off ebay) that the sensor for the speedometer is in the gearbox. Is the speedometer programable, or do I have to take other measures to get it to read accuratly. (at least as accurate as it is now which is about +4mph @55mph)

[DEcosse]

(If you could go into your USerCP and edit your 'favourite bike' to include the year that would be helpful, MotoZiggy, so other members can identify to which model your question relates)

You can certainly change it in the map with Tuneboy - it's possible to change the gearing ratio. I honestly don't know if possible another way (like by Triumph gameboy for example?).

You could also change it by using a speedohealer but by the time you invest over $100 in that, may be worth considering TuneBoy for the other benefits - plus all done in software, no parts to add!

Note that any correction you make for speedo will adversely change your odometer at same time - odo should be pretty accurate so when you adjust speed down by about 8%, your odo will now rack miles lower by same degree.

[Darkhorse]

Im pretty sure that with a tuneedit you can go to tune constants and change the speedo constant there. Stock is something around 2655 er somethin.

[thewolf-Oz]

Originally Posted by DEcosse

Note that any correction you make for speedo will adversely change your odometer at same time - odo should be pretty accurate so when you adjust speed down by about 8%, your odo will now rack miles lower by same degree.

If you're changing because of a sprocket you'd want the odometer to change too though wouldn't you?

[DEcosse]

Originally Posted by thewolf-Oz

If you're changing because of a sprocket you'd want the odometer to change too though wouldn't you?

Of course - my warning was about adjustment purely for calibration of the speedo error - with stock sprockets the odo is quite accurate therefor 'calibrating' the speed will mis-calibrate the odo.

Obviously if you re-calibrate because of a final drive ratio change you want both speedo & odo to be affected accordingly (& they will be)