A couple of thoughts.........
I got a bit of a surprise this year at Blue Max Kart club in Davis California when going into the right/left "S" turn (really almost like a chicane) at the bottom of the hill during qualifying as I found myself at full throttle going into this tight section.
I was lucky that I had some years ago experienced a runaway engine when the cylinder base gaskets blew out on my KT 100, and I very rapidly got on the brakes and throttled the intake by putting my hand on top of the air box, thereby covering the intake holes in the air box.
Why? The throttle return spring on the carb had failed and the return spring up at the throttle pedal definitely did not close the carb.
Got it fixed before the first heat by swapping a carb from a spare engine in my trailer, and went on to take first place amongst club members in the F-100 class that day.
Those little wound springs on the carbs are not as reliable as one might imagine.
Now, as regards vintage karts, I have been finding that the cables from the aluminum block on the side of the frame seem to want to bind a bit on the 820's that I typically run, and I have taken to adding an auxiliary spring at the engine. A little bent steel bar bolted to the intake manifold, and a tension spring from there to the swivel on the carb shaft seems to work really well. I'll need to take a photo and post here when I get a moment.
In other news, faithful readers might enjoy seeing the way I handled the throttle business on my First Edition of the Kalifornia Nykes. Lots of details on this build are posted here on the Forum, but here's a photo of the assembly I mounted on the bottom of the frame at the seat.
What you might find interesting is that this assembly provides for a positive forward stop and a positive return stop. I really don't like the idea of using a fully-compressed compression spring as a positive forward stop, as the springs tend to kind of miss-align as they are fully compressed, and potentially end up allowing a lot of force to be exerted on the throttle shaft at the engine - when your (my) energetic foot is pressing hard on the throttle pedal, and really trying to push the throttle at the carb past wide open.
I've also attached an illustration of the assembly which provides details.......
Ciao!
I got a bit of a surprise this year at Blue Max Kart club in Davis California when going into the right/left "S" turn (really almost like a chicane) at the bottom of the hill during qualifying as I found myself at full throttle going into this tight section.
I was lucky that I had some years ago experienced a runaway engine when the cylinder base gaskets blew out on my KT 100, and I very rapidly got on the brakes and throttled the intake by putting my hand on top of the air box, thereby covering the intake holes in the air box.
Why? The throttle return spring on the carb had failed and the return spring up at the throttle pedal definitely did not close the carb.
Got it fixed before the first heat by swapping a carb from a spare engine in my trailer, and went on to take first place amongst club members in the F-100 class that day.
Those little wound springs on the carbs are not as reliable as one might imagine.
Now, as regards vintage karts, I have been finding that the cables from the aluminum block on the side of the frame seem to want to bind a bit on the 820's that I typically run, and I have taken to adding an auxiliary spring at the engine. A little bent steel bar bolted to the intake manifold, and a tension spring from there to the swivel on the carb shaft seems to work really well. I'll need to take a photo and post here when I get a moment.
In other news, faithful readers might enjoy seeing the way I handled the throttle business on my First Edition of the Kalifornia Nykes. Lots of details on this build are posted here on the Forum, but here's a photo of the assembly I mounted on the bottom of the frame at the seat.
What you might find interesting is that this assembly provides for a positive forward stop and a positive return stop. I really don't like the idea of using a fully-compressed compression spring as a positive forward stop, as the springs tend to kind of miss-align as they are fully compressed, and potentially end up allowing a lot of force to be exerted on the throttle shaft at the engine - when your (my) energetic foot is pressing hard on the throttle pedal, and really trying to push the throttle at the carb past wide open.
I've also attached an illustration of the assembly which provides details.......
Ciao!
Jim Waltz, West Sacramento, CA