Tech Tips For TAG Leopard

[Bryan W. Joplin]

We have several new members to our TAG racing group and on behalf of our established racers, I would like to welcome you to the fun. Experience has shown that there are preventable equipment failures occurring to first time karters mainly caused by maintenance. Therefore, I propose providing a series of papers addressing maintenance, repairs and general engine tuning start points. All this information is available on the internet, in manuals or the knowledge base of the membership. The intent here is to consolidate information and provide a starting point for enjoying your new hobby. Below is a paper addressing Maintenace of Chains, sprockets and drivers. Please let me know if discussion papers of this nature are helpful. Do not hesitate to ask questions or propose topics for discussion.


Chain maintenance-- Inspect the chain and axle sprocket for damage, including cracked links each time you come off the track. (especially, if the kart engaged in off-roading) Look for nicks in links caused by striking curbing. Observe the edges of the axle sprocket for proper chain alignment. ( see chain alignment below) Lubricate the chain each time with a high quality chain lube designed for karting. The chain and axle sprocket should be removed and cleaned after each hour of run time. A damaged link in a good chain can be replaced with extra links saved from sizing your chain. Check the chain. A broken chain can become lodged in the engine clutch cover, causing more damage than just chain replacement.
I still see racers cleaning their chains by dipping the whole chain into a solvent, or washing the chain with a heavy solvent spray. Do not do this. Solvents wash the lubricant out of the chain pins. The spray chain lubricant does not replace this lube. Do not even spray a degreaser on your chain, it goes right to the pins. Clean the chain by spraying degreaser on a rag and pulling the chain through the rag. Use the following guidelines to get the most out of your chains and sprockets:
1. The Chain
a. Checking Chain wear-- wrap your chain around a good axle sprocket. Lift up on one of the fully engaged links. A new chain on a new sprocket will hardly move. The more wear, the more lift. If the chain lifts over half a tooth on a good sprocket, replace the chain.
b. Chain Alignment---Good chain alignment is key to the life of your chain, axle sprocket, drive sprocket, clutch drum bearing and washers. If the edges of your axle sprocket are galled, or you are eating clutch drum washers, the chain is not aligned. Align the axle sprocket using a straight edge or alignment tool, checking it in 1/3 increments. (I use a 12in aluminum carpenters level. It is straight and the flat edge can be held against the axel sprocket without rocking) You will notice that with each 1/3 turn, the straight edge will drift back and forth across the driver. Balance the drift over the driver with the amount the driver floats on its bearing. If the straight edge drifts more than the thickness of a drum washer, something is bent. Check the sprocket and sprocket hub for damage. Discard a bent sprocket. A slightly bent hub can be repaired. If you have a floating axle hub (supposedly self aligning) good luck. I got rid of mine and went to a fixed hub. I could never balance axle float with driver float. You may have better luck.
c. Chain Adjustment--- Follow the manufacturers recommendation for chain adjustment. Be careful not to over tighten. A chain that is too tight has been blamed for crank failure, cause by chassis flex. Chassis flex can tighten the chain even more and exert heavy loads on the crank. When sizing your chain using a chain breaker, be careful not to reinstall the chain pin too tight. A tight pin will not allow the chain to flex properly, when it wraps around the driver and axle sprockets.
2. Axle sprockets---Clean and inspect the sprocket after each race or practice day. Look for damage caused by poor chain alignment, or striking track and curbing. While the gold sprockets are the most common seen at the track, try the “Black Magic” sprockets. I have about 6 race days and some practice on an 80T. When washed, it could still be sold for new (including the black coating). These sprockets are cheaper than the gold and have good wear characteristics.
3. Drivers
a. Checking Driver Wear---Clean and inspect the driver with your other maintenance. Replace the driver when the teeth develop a pronounced hook. Try the aftermarket one. The aftermarket driver costs less and lasts longer. I have a full season on my driver, and it is just starting to show wear. That’s 20 plus race days including practice.
b. Driver Installation/Removal---If driver screws are not installed correctly, they will back out or break off. Install the driver using red loctite. Tighten the screws as tight as possible without breaking your allen wrench, or follow the torque specification in the manual. When removing a properly installed driver, the allen screws have a tendency to strip out or break off, unless heated. Your best investment is a propane plumbers torch. To remove the screws for driver replacement, heat around the screws with the torch. The loctite will melt, the hub expand and the screws will come out. (I have never stripped or broken a screw using this procedure) If the allen head of a screw is stripped, pick a torx wrench just larger than the allen hole. Drive the torx into the hole and remove the screw. When using loctite anywhere else on your kart or engine, heat will break the bond. Heat is your best friend, when removing bolts. Heat must be used to release red loctite.
c. Driver selection--- As a rule of thumb, use the smallest driver you can. The 10T driver has about a .6% torque advantage over an 11T. This means a 10-80 ratio has about the same torque, but greater axel speed as an 11-89. While the percentage is small, at 16,000 rpm, the additional pounds of force start to add up.

Bryan

[bomccown]

Hey Bryan,

Thank you for taking the time to write this up. As a new member, this information is invaluable. I will be printing and laminating it. I will do the same to any other articles you or other experienced karters will take the time to write.

Thank you again, Bo...

[Jean Michel Gaston]

Wow, this is a great post. Thank you very much.