2012 Yamaha Nytro xtx speed reading slow

Speedometer reading slow, says 50kmh when we are doing 100kmh and is steadily getting worse. The drive shaft bearing is relatively new about 1000kms and seems good, the gear looks good no teeth missing,new speed sensor as I was thinking that is what was wrong and I didn't fix it. Could it gauge cluster or the ECU? Or? Sled has Power Commander 3 because it has cold air intake, magnflow muffler and mbrp header don't imagine that it would have any effect on the speed reading.

I'm guessing all the modern Yams have these ground clip devices and
maybe one in the harness from speedo as it would need just one poor
contacting pin / leg. Saw some similar threads posted below but no response
on what fixed them (or not)..
Ground was suggested in the one post.
Ron

try adding a ground from the frame to one of the ground blocks as it is old enough that there could be corrosion where it mounts to the engine/frame.

hydraulic yam said:

I'm guessing all the modern Yams have these ground clip devices and
maybe one in the harness from speedo as it would need just one poor
contacting pin / leg. Saw some similar threads posted below but no response
on what fixed them (or not)..
Ground was suggested in the one post.
Ron

Click to expand...

Hmm ok I'll have to look into that, I thought I had gone through all the ground blocks for other issues and they all seemed good but maybe I'm missing one. It was slowly getting worse during the course of the winter. Thanks