Ted Hamilton
Helmet Painter / Racer
Pulled from cache:
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robin,
The article you posted has some good information but you do not need to modify the butterfly to make your KT100 start easy, idle and run well on the track through the whole range.
I have been helping a new karter with his KT100 sprinter for a couple months and he has made several trips to the track by himself to practice and this is is routine.... he plugs in the starter and hits the button and the motor starts and sits there idling without touching the throttle pedal while he puts on his helmet and driving apparel. The he pushes the kart over to the grid area and gets in and drives his 10 to 20 laps without touching the carb. The kart is equipped with a 2 disk L&T wet clutch that does not get hot even though he does not lift the rear and let the wheels turn while getting dressed.... the idle is low enough to allow the kart to sit still without a problem.
I set the carb up for him as follows:
Arm height is set with the diaphram end fork approximately .020" above flush with the circuit plate. The pop off pressure is set at 18 pounds (stock spring)
Low speed needle is set and left at 1.25 turns and the High speed needle is set at one half turn. The idle adjustment screw is backed off until the butterfly is fully closed and then brought back until it just touchese the lever on the end of the throttle shaft and then is screwed in 1 full turn.
You should see the people at the track stare at my guy when he walks across the pits pushing his KT100 powered kart while it is idling away like a motorcycle... they never see that but only because the majority of the guys running the Walbro carbs set them up wrong and conclude that they won't or can't idle.
Start with those settings and fine tune... you will probably end up a little leaner on the high speed jet since you are not running long stints.
Good luck
Steve O'Hara
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robin,
The article you posted has some good information but you do not need to modify the butterfly to make your KT100 start easy, idle and run well on the track through the whole range.
I have been helping a new karter with his KT100 sprinter for a couple months and he has made several trips to the track by himself to practice and this is is routine.... he plugs in the starter and hits the button and the motor starts and sits there idling without touching the throttle pedal while he puts on his helmet and driving apparel. The he pushes the kart over to the grid area and gets in and drives his 10 to 20 laps without touching the carb. The kart is equipped with a 2 disk L&T wet clutch that does not get hot even though he does not lift the rear and let the wheels turn while getting dressed.... the idle is low enough to allow the kart to sit still without a problem.
I set the carb up for him as follows:
Arm height is set with the diaphram end fork approximately .020" above flush with the circuit plate. The pop off pressure is set at 18 pounds (stock spring)
Low speed needle is set and left at 1.25 turns and the High speed needle is set at one half turn. The idle adjustment screw is backed off until the butterfly is fully closed and then brought back until it just touchese the lever on the end of the throttle shaft and then is screwed in 1 full turn.
You should see the people at the track stare at my guy when he walks across the pits pushing his KT100 powered kart while it is idling away like a motorcycle... they never see that but only because the majority of the guys running the Walbro carbs set them up wrong and conclude that they won't or can't idle.
Start with those settings and fine tune... you will probably end up a little leaner on the high speed jet since you are not running long stints.
Good luck
Steve O'Hara