X11 vs. BB gearbox speedo sensor

[dwr 5]

Hi,

 

Just FYI, since I had to find out;

 

One of the differences between an X and BB is related to the gearbox speedo sensor. The sensor itself is the same/interchangeable, and in the same position, but in an X11 it picks up from 4th gear on the mainshaft, (the one the clutch is on)  whereas in a BB it picks up on 5th gear. This is because the positions of the various gears on shafts differ between an X and a BB.

That results in an X11 with BB engine getting speedo overreading of about 15% compared to a standard speedo/engine (which also typically overreads somewhat, remember..). So the overall difference will be "quite high", perhaps around 17% or so..

Lowering the rear wheel gearing (e.g. 16:43) will make this worse, not better. 

 

The only solution for this is a Speedohealer type device.

 

kr  D.

[dwr 5]

Update, for anyone interested, the calculated speedo overread is 19% with 16/44 gearing (and 16/44 is roughly right for a BB engine in an X11, possibly 16/45 would be better). I have tested this on the road and it's pretty much correct.

 

kr  D.

[fast_eddy 712]

Nice one Dermot