Speedo error

[dubepj]

My speedometer works but is inaccurate. When checking against wife's car it reads about 52 MPH when she is going 60 MPH. That's pretty bad. Or if you prefer KMPH It read 85 KMH when she is travelling 100 KMPH
My buddy's speedometer is also out nearly the same
Is this a common issue on these Xs650.
Or is the magnet in there weak?
Or what else could cause this?
Thanks

 

[gggGary]

On a stock tire the speedo will usually will read a little high.
Mostly by design, due to European laws.

 

[650Skull]

https://www.xs650.com/threads/early-model-70-71-instrument-rebuild-rejuvenation.31305/

This is from an early XS1/1B gauge. Principals are the same so go down to post #10 and read the list of "commonly found problems". The thread does go through the full dismantling of the components and a clean. gets involved.

 

[Max Midnight]

On a stock tire the speedo will usually will read a little high.
Mostly by design, due to European laws.

In the UK that is -0, +10% +4 k.p.h.

 

[xjwmx]

Sometimes it's a needle lubrication problem that'll fix itself after a few days. There's no geared connection to the needle, just magnetic influence from a spinning part. I've had them be really sluggish from being removed and put on the shelf upside down for a few days, but return to normal after some riding