Motor BM130 with a special Burco clutch, Vevy pipe and dual hartman 293 carbs.
Some times we get lucky......very lucky. Went out for first practice and was a literal missle. Kart was great and one of those magic days where everything was just hooked up.
Second practice: Went out and ran a few laps and noticed something shoot to the right at the end of the long straight where I was running about 90+ MPH as I went into a left hand corner. I knew right away it was my wheel nut. When I hit the short straight I looked down and saw the wheel walking out and off the spindle. I turned a little to the left and the wheel came back on and I slowed and went across the track with my hand in the air, stopped by a hay bale. All this at about 70 MPH with hay bals on either side. I was lucky.
It was my first time loosing a "berry clip"
. I was lucky 
. When I got back to the pits I put another one in and noticed that if you moved everything around just right the valve cap would make contact with the clip. I replaced them with cotter keys and dominated the race. Even though the special clutch broke a piece off and locked the clutch up direct drive. Some days we get lucky.....some days we won't talk about. When you really think about it, in US karting "Berry Clips" came on the scene about the time Virg said. Early 80's, when the norm was a recessed wheel to protect the clip from a rub or knerf bar. On a Vintage Kart with no dish on the wheel I will always run cotter keys. Cotter keys will be in all my Vintage Karts for both safty and looks. It would be a shame to tear a kart or yourself up because a clip came off.