I also have tried a homebuilt sidecar, actually platform. on a hopped up CB 750.
We ran it a bit on a dirt track oval. I was on the platform, and took great delight in self-describing myself as "the monkey" Bad part is, I am uh rather portly, and not really as agile as the task demands.. lucky we were turning only one way.
I have not yet ran at Bub, but have ridden it there solo.. Hope to make it there by bike this year, but if I do it will be without hack.
To Beairsto, I seen one of your racers out in BC, on the dirt, the yellow snowmobile engine job...
maybe next year I will get it on the track, or at least RWYB..