Christa’s 2013 Ride- 2013 Top Kart Twister
By Mike Kojima
Karting is perhaps one of the best training aids for racing. Karts are much cheaper to operate than cars and it’s usually a simple deal to get your kart ready for a weekend of fun compared to your race car. Most of us agree that Karting is probably harder than cars as well, more akin to a formula car than a sedan. The MotoIQ crew goes karting frequently to get a speed fix without spending a lot of money.
Karts are also good training for future drivers that are too young or small to drive a full sized car! Christa Kojima has been karting ever since she was about 8 years old, starting in a 50cc kids kart, then moving up to a 100cc clutch kart at the mandatory age of 9. Now as she approaches 12 she will have to move up again from her current class of HPV-1 to Jr’s.
Unlike the smaller Cadet kart she drove in HPV-1, a Jr class kart is a full size kart, some of them have a little shorter wheelbase but the dimensions are mostly equal to an adult kart. There are several Jr classes but Christa is going to be in Jr2 which allows powerful 125cc TAG electric start engines using an inlet restrictor.
|Christa’s kart is a 2013 Top Kart Twister. Christa has been driving Top Karts and we chose the Twister for her because we feel that Top Kart makes a better chassis for lighter weight drivers. The Twister features a chassis constructed of 30mm chromoly tubing with 32mm cross bars. Since karts rely on chassis flex for tuning, we felt it was better to start with a small tube chassis. Top Karts have a reputation for being the Kart to beat in Cadet and Jr Classes. We bit the bullet and bought a state of the art new chassis from Empire Karts. Until now Christa had been driving used second hand stuff. We decided to splurge this time because she still loves to drive as she has gotten older and is committed to the sport.|
|A modern racing kart is not a toy, having more in common with a formula car than a fun kart powered by a lawnmower engine. The chassis is highly adjustable to tune the handling balance. The bodywork is aerodynamically designed to reduce drag, produce some downforce and must be certified by the FIA for impact protection. It is important to have a good shop to support you, especially when starting out. We use Empire Karts in Redlands California because they have always given us awesome customer service and have always been helpful with our tech issues.|
|Christa’s kart is powered by a PRD Fireball engine, a 125cc water cooled two stroke. Unrestricted it produces about 28 hp at 16000 rpm. For Jr class it is restricted via a carburetor plate and airbox inlet restrictors to around 22 hp. The engine has a 7.5:1 compression ratio, a 22mm Tillotson pumper carburetor that uses crankcase pulsing to pump the fuel, CDI ignition, carbon reed valve induction and a tuned expansion chamber. The kart is capable of over 80 mph.|
|A large aluminum radiator provides the cooling.|
|Like most water cooled karts, the water pump is driven off of the rear axle.|