2006 GSA final drive ratio
 

My FD went @ around 55,000 miles and I had a 2008 FD unit almost new kicking around from a job lot i bought. Knowing it was a different ratio I fitted it and the ABS sensor for that unit but lost the speedo function. I'm guessing what I have done has thrown a code up but can anyone tell me if I can retrieve the function of the speedo once this has happened...?? ( One for 'Touring Ted' maybe..??) .

What FD did you have before ? What year/model is your bike ?

The speedo and ABS will work if everything is working properly even if you have stored fault codes. You 'shouldn't' have to clear codes.

I'm guessing you have conflicting signals from the front and rear wheel speed sensors. Especially as you have no speedo function.

Unplug the rear speed sensor and see if your speedo comes back. Then report back.

FYI. The speed sensor makes no difference. It's the spacing on the rings of the ABS rings. They need to match for the computer. There were differences over model years. Especially when they changed from Servo ABS.

Ah, now we're getting somewhere, glad you chimed in here. The bike is '06 and the new FD is '08. The sensor on the new fitted FD is larger in diameter and I believe the flip year is '07-'08 which would suggest your comment above about 'matching' spaces on the ABS ring is where my issue is (thanks) and I'll disconnect and take it for a spin TODAY... Thank you kindly TT.....

Yes. There are two different sizes of sensor on the 1200GS.

I think there is Pre 08/2006 and post 08/2006. But there are over-laps with the GSA/RT etc. It's a bit of a mine-field.

I'm not certain, but maybe you can fit a matching ring for the front wheel to the same generation as the final drive.

I don't know if the computer will know the difference in the years. Or if it just wants a matching signal.