OK, let’s start with the brake. If there is 1/16 to an 1/8 inch gap between both sides of the rotor to the brake pads, we’ll assume that the brakes are not dragging. Now, let’s start with two things, the carb and the clutch. How much do you know about them and have you made any changes to them?
If the engine dies while idling, wouldn’t be too concerned unless it doesn’t fire right back up.
Let’s check the clutch first. Put the kart on the stand with the tires firmly bolted on. Fire the engine, let it warm for a bit. With a little throttle, you should be able to lock the rear wheels without the engine dieing. The clutch shouldn’t be set to stall until 7,000 RPMs. Typically, the stall speed should between 8 and 9K. When adjusting the clutch, start at the bottom and slow increase the stall speed. Never start a stall speed at 11K and work your way down. If you do, the clutch will just turn into smoke.
Now for the carb. Start with a clean air filter. With the filter off, make sure the butterfly is wide open when the throttle pedal hits its stop. If the carb hasn’t been rebuilt in a while, consider a rebuild kit. That way you’ll know the pump is in good condition. Do you have any idea what the fulcrum height is and the pop off pressure? Do you have a Flex-T in the low speed jet? Since there is no choke on this carb, the fuel mixture has to be on the rich side to get it to fire. Once it’s running, it will need to be leaned out with the low end jet. When you start to take off, does the engine rev cleanly or does it like BLAA, BLAA, BLAA. The carb could be just too rich. You never said where you had the needles set to. Every carb is going to be a little different and the pop off is going to effect the needlee setings. Try a pop-off between 9 and 11 psi, and the needles set to 1.5 to 2.0 turns out from the seat for the low end and between closed and a 1/4 open for the high.
Make sure you have the right plug in and that it is not oil fowled.
LAD Specialties customer / tony kart / rotax / kt100