Hi John,
Before I sold you the 53 KK, I did went to a dyno shoot out with it for fun...
Big evos in the day with some having readings of 125bhp or so...
So we strapped the KK on the road rollers and we couldn't pull 4th gear at all...
Eventually managed a 3rd gear "run" and that read, wait for it, 11bhp...
It still did around 90mph and I would fight and beat evo Sportsters no sweat...
I have never trusted bhp figures for anything... But what I can compare is all the bikes I've had...
The fastest by a long way was my 1st Sportster, a 76 XLH, on which I could, no kidding, put both tacho and speedo needles on their stops while the bike was still accelerating...
Next was a 66CH fitted in the States with an SU carb, not far behind... It had buckhorns and the leather flapping would hurt your arms after a while.
Next is my 54 KHK, as fast as a "normal" Sportster, but with way more torque and a lack of P cam effect that the X gets around 4000rpm... Just straight endless pulling from the word go.
The way I use engines means I've never noticed lack of humph in the low revs.
The way the 53 KK ran was strange to me, it would go fast and stay there despite the huge bars, but it took a while to get there, hence the desire never to shut down too much!!!
I've enjoyed them all, that's the main thing, innit???
Patrick