New Kart – Checklist

  • Mount four tyres and pump to

12PSI for Medium grip tyres such as DFM, MG Reds

8PSI for Soft tyres such as Mojo or MG Yellows

18PSI for Hard tyres such as Dunlop SL1s

  • Fill radiator with distilled water and approved motor race inhibitor. N.B. The water level will decrease after the engine starts and will need to be topped up.
  • Rear wheels – The outside width of the rear tyres should be set at 1390mm for 125cc, 1380mm for Junior and 1350mm for Cadets. Ensure that the distance from the inside of each tyre to the large axle bearing is the same on both sides.
  • Check that the following are tight
    • grub screws on rear axle
    • bolts on sprocket carrier
    • bolts on brake disk carrier
    • bolts on rear wheel hubs
    • nuts on front and rear wheels
  • Front Wheels – Use spacers (20 mm) on the inside of each wheel. Use the remaining spacers on the outside. The wheel nuts should not be too tight. You should be able to turn the axle wheel spacers with fingers.
  • Connect Battery leads
  • Install the correct spark plug and plug the high tension lead on. See section Spark Plug selection
  • Gearing – Use a sprocket combination to give 15,000 RPM for most engines and 13,800 for Rotax, 12,500 for Rotax Restricted.
  • Mix fuel (premium unleaded 98 octane) in a fuel approved container
    • Rotax 40:1 (33.3:1 if ambient temperature exceeds 25 degrees Celcius) – use Synthetic racing Kart Oil• Leopard RL/Fireball – 16:1 (Castor based racing kart oil)
    • Leopard X30 – 25:1
    • Yamaha – 20:1 (Castor based racing kart oil)
    • Rotax 40:1 (33.3:1 if ambient temperature exceeds 25 degrees Celcius) – use Synthetic racing Kart Oil
  • Pour fuel into kart’s petrol tank. The fuel contains oil to lubricate moving parts within the engine. Therefore it is important to ensure fuel is in fuel lines and carburettor before starting the engine. There are three options to fill the lines with fuel.
    • Hold hand over air intake or carburettor air intake and turn the engine for 5 seconds. This causes the fuel to flow through the line quicker than normal.
    • If Rotax – Remove the line from petrol overflow tank and blow into it with your mouth. This will pressurise the petrol tank and force the fuel along the fuel line into the carburettor. Ensure the fuel flows into the carburettor.
    • Take the spark plug out and turn engine for five seconds whilst covering air intake or with hand. (ensure that plug is still plugged into the cap and that the side of the plug is resting on the metal of the top of the engine)
  • Start the Engine
    • If on a kart stand, ensure that the wheels, chain and brake disk are clear of the trolley. Avoid running the engine on a stand as kart engines are designed to have a load.
    • If 125CC – Press the start button (If Rotax, turn the ignition switch on first). If the engine does not start in five seconds, stop and repeat after five seconds.
    • If Yamaha – turn the Low jet to 1 1/2 turns to star. Once started, move back to the original position
  • Running in – Please refer to run-in procedure from your shop. Generally, do not over-rev the engine during the first 30 minutes of operation. During this period, do not drive at a constant speed. Regularly check that the brakes provide sufficient resistance to stop the kart.
    • 125CC water-cooled Engines – Watch water temperature gauge is within the normal range (45C to 65C). During the run-in phase. Once the engine is run, the optimum temperature is approximately 55C but may increase to 75C in summer.
    • Check, check and double-check during and after the run-in. It is possible for bolts or nuts to come loose. Pay particular attention to the bolts on the brake disk and sprocket carrier. The exhaust manifold bolts will definitely need tensioning.
    • If you hear anything out of the ordinary when driving, stop immediately. We have seen many catastrophic engines failures that could have been minimised. e.g. a failed main bearing will make metallic sounds however the performance of the engine may not be affected. Driving even a short distance will lead to complete engine failure ( almost no reusable parts)
  • Excess hours on engine. The probability of engine failure increases dramatically after a certain number of hours. Pistons and other components can crack and break. A regularly serviced engine is unlikely to fail.
    • Incorrect spark plug, carbon build up in the engine or incorrect jetting can cause unwanted detonations to occur in the combustion chamber which will lead to skyrocketing engine temperatures and starting difficulty.
  • Rotax
    • use the correct jetting for conditions. If the engine backfires whilst driving, stop immediately and change the jet.
  • Engines with radiators
    • Avoid over-revving if engine temperature is less than 45C This may lead to a “cold seizure”
    • Pay particular attention to jetting – particularly the high jet. A slightly lean high jet will cause engine failure.
  • Yamaha KT100S
    • Pay particular attention to jetting – particularly the high jet. A slightly lean high jet will cause engine failure.