Technology Information
Thank you for purchasing a SwedeTech Engine. The following is a basic guide and helpful hints to help you fine-tune your SwedeTech TAG engine.
100cc/125cc Leopard
If you received your engine without an engine mount, you must make sure the mounting surfaces on the bottom of the cases, both sides of the steel vibration damper and your engine mount, are all flat and parallel.
When adjusting chain tension, always remove the springs that hold the pipe to the cradle, this will eliminate bind from the pipe while adjusting. Replace springs when done adjusting tension. Snug up the butterflies and with a straight edge; line up the rear sprocket to the front sprocket. Never use old or kinked chains. Try to achieve a ½” to ¾” play in the middle of the chain. You must also rotate the rear axle to make sure there are no tight spots (watch your fingers). Next, tighten the butterflies, snug up the engine-stop, and tighten the jam nut. **Do not use the engine stop to adjust the chain.** The engine stop should lightly touch the engine mount. Using the engine stop to adjust the chain may cause improper tension of the chain. Always run an engine stop. Make sure you have maintained the appropriate play in the chain.
We recommend the SwedeTech Throttle Cable and Bearing Kit. The SwedeTech Throttle Cable and Bearing kit bolt to the throttle shaft to eliminate broken carburetor barrels. Inspect the butterfly position inside the carb to make sure the butterfly sits perpendicular to the carburetor bore. Make any necessary adjustments to the throttle cable or pedal stops. Do not allow butterfly to over-rotate in bore (past full throttle), this will break the throttle cable if not properly set up.
Always install the carburetor with the fuel inlet/filter on top. Also make sure to lift up the carburetor while tightening the 2 nuts. This will line up the carburetor pulse hole with the intake pulse hole. Never set an idle; let the throttle shaft plate barely touch the adjuster screw. Check with your tech inspector if it is legal to cut you’re air-filter and any extra rubber flanges off right inside the air box. It is recommended to utilize the external screens on the inlet tubes. Also ask the tech director about the following item. Smear a heavy-duty axle bearing grease on the bottom of the airbox to potentially stop any debris from entering your engine. To properly install your airbox, you will want to fabricate a cradle mount that will allow the airbox to sit in a non-binding manner. Use rubber O-rings to secure the airbox to the cradle. Always check with the tech director on legal use of airboxes. Some rules are open and non-tech while others you must run the manufactured supplied airbox.
For a proper ground wire connection on the coil, place the spade connector onto the coil and zip tie the loose wire to the coil. Next, apply a small amount of silicon inside the plastic spade connector to eliminate excessive vibration from the wire to the crimped spade connector. Route the coil ground wire to the battery ground wire and zip tie together for neatness.
125cc Leopard
The unpainted ’06 pipe performs better over the pre ’06. Only use flex pipe (not solid). With a flexible tape measure, measure from the face of the exhaust flange (where the nut and/or washer touches) back around the outside (the longest distance) of the exhaust header and pipe to the middle of the 1st weld. The engine performs best around 15 ¾” +/- ¼”. Longer flex will provide more low-end power with some loss of top end power. Shorter flex will provide more top end power with some loss of low-end power. You may want to test different lengths because each engine package may prefer slightly different lengths within the above range. This length can change depending on track length, configuration, weather conditions, or driver preferences.
125cc Leopard JR 25mm Header
Low Speed – 1 7/8 – 1 3/4
High Speed – 5/8 – ¾
Flex – 16 – 16 ¾
** When using the Jr. Headers, pay close attention to cracks or breaks on the header. **
100cc Leopard
At this time you must use the painted pipe that comes with the engine, per the current legal rules. Use the shortest possible flex, so the pipe barely touches the exhaust flange.
100cc/125cc Leopard
Use 5 to 6 springs, utilizing a criss-cross pattern, secure the pipe to the exhaust header. You do not want the pipe/flex to extend the length while driving. Also take the time to line up the cradle type bracket and use 2 springs to secure the pipe to the rear cradle. (Do not use hose clamps.)
Water flows from the bottom of the radiator to the center (face of the impeller) of the water pump, the water then flows out of the pump to the lower left side of the cylinder inlet. The water then exits out of the head and back to the top of the radiator. Always keep hoses as short and straight as possible, without big loops or any kinks. No other routing is correct. Always lift up the go-kart to, at least a 45 degree angle with the radiator highest, to get all air-bubbles out, when filling up a dry system.
Make sure the gas tank vent nipple, the external catch bottle nipple, and the bottle in itself (if you are utilizing one) have at least 3/16 holes in them.
Use at least a VP MS98 or equivalent fuel, with a castor oil of a 16:1 ratio, this equals 8 ounces per gallon. After each session, make sure you spray lube on the clutch bearing.
BREAK IN
If you paid for the Dyno Break in, there is no need to repeat the break in procedure. Make sure the engine is at proper running temperature before you begin your track session.
Start to tape up your radiator so the running temperature is around 140 – 150 degrees Fahrenheit. Begin with a carburetor low-speed jet 2 1/8 turns out and high-speed 1 1/8 turns out on a low-density altitude day/track. On a high-density altitude day/track (+4000ft) start around 1 7/8 turns out on a low-speed jet and 1 turn out on a high-speed jet. On the track accelerate with full throttle out of the turns up to 11000 rpm. When you are off the throttle, be completely off of it, and then blip the throttle a few times. Let the rpm come down and then full throttle again, up to 11000 rpm, then completely off again with a couple of blips do this for 4-5 laps then increase the rpm to 13000 for another 4 –5 laps with the same procedure as above. Then increase the rpm again to 15000 for 4-5 laps, then again to 17000 rpm for additional 4-5 laps. When you have completed 18-20 laps you can now start to “get on it” and lower the water temperature to its optimum running temp. Of 125 – 130 degrees Fahrenheit.
High speed jetting usually ends around 1 1/8 – 7/8 turns out, low speed usually ends around 2 1/8 and as low as 1 3/8 turns out. Jetting is all related to track length, tire/chassis, grip, driver ability, weather conditions, and gasoline. It is always easier to start rich and lean out from there.
IAME recommends highest rpm at 15000. However you will get faster lap times if you reach the low to mid 17000 rpm. This will then of coarse increase your rebuild intervals. If you rev above 17000 rpm, we recommend 6 to 8 hours between complete rebuilds. The best usable power-band is between 8500 – 17000 + rpm. Do not allow the engine below 7500 – 7600 rpm.
When working on your engine, be very careful around the intake and carburetor. There are many little adjustments, such as the pulse hole line up and proper carburetion setup. Do not disassemble carburetors or reed petals from cage, as these items are inspected at the shop. These engines are very sensitive, any little alterations to the set up will slow it down, so please if you have any questions or concerns call us. If you have been pulled apart for tech, please call us after the race weekend so we can properly set you back up.
