250 Crank/Balance shaft?

[200Chaos]

Hi all, I've been rebuilding my Kdx 250 following a snapped input shaft. I've now gotten a little stuck. Now not knowing much about the KDX (although the knowledge is increasing rather rapidly!) this question may seem stupid.

My problem is I can't find any info in any schematic or service manual on this part. It looks to me like a balance shaft, it joins onto the crank with a woodruff key and sits behind the flywheel. I take it that this needs to be set at the right point of the stroke? I've got 2 service manuals for a 93 250 and neither show the part. Any help would be much appreciated. Again sorry for lack of coherency on the part!

[KDXGarage]

what country model is the bike??

[200Chaos]

I believe it's a Japanese import to the UK as far as I know. There isn't any more info on my log book. There's a good chance it's an SR.