Did a track day at Brands Hatch in 2006 on my near-stock Triumph Bonneville. I went in the slow group because of the bike making 50bhp, but I shouldn't have bothered.
I managed to lap an Aprilia RSV1000 and had a particularly good time showing up a guy on a CBR600. He'd pass me in straights, I'd pass him in corners; boot out, flat track style!
He got so aggravated that he eventually made a particularly stupid overtake, wound up taking out my front end, and got black flagged. 1 highside and 3 cracked ribs later, we both knew the truth; it's the rider, not the bike.