Fork oil level - why spacer in?

[Okanagan]

Does anyone happen to know why, for the F650GS, the BMW procedure to set the 100 mm air gap for the front forks requires that the spacer (only) be installed in the fork leg? Why didn't BMW simply specify a larger gap without the spacer installed?

The spacer is hollow but it does displace enough oil to significantly raise the level.

Installing the spacer to measure the air gap means that you have to remove it once the air gap is set so that the spring can go in first. I have done this three times now so I know how and the procedure does work. But why this awkward procedure?

I have yet to see an explanation and I have certainly looked for one.

 

[mgo]

Whatever the reason, it definitely sounds very odd.