by the Qld Superkart Club
Looking for an easy way to get into kart racing on long circuits?
If you’ve ever watched a Superkart race and wondered how to get involved, or thought it must cost a fortune, the 125NGB might be just the ticket. The 125NGB (also known as Rotax) can be an inexpensive and reliable way to go racing on longer tracks like QR and Lakeside.
So, what are they?
A 125NGB superkart is basically a sprint kart with a few minor modifications to meet Superkarts technical regulations. There are also a couple of local manufacturers who make a chassis specifically designed for the class.
As with sprint karts they have rear brakes only and 5” wheels. They are usually fitted with a nose cone to improve aerodynamic efficiency on the longer straights seen in Superkarts.
What modifications are needed to convert a sprint kart for Superkart racing?
There is not a lot you need to change on a sprint kart. They must have a rain light. Inspection holes must be drilled in the tie-rods to ensure the have enough thread engagement. Mounting bolts on the brakes need to be drilled and lock-wired. To increase top speed for the longer tracks, gearing needs to be changed. This is done by fitting a 16 tooth front sprocket and changing the rear to suit the track. A front nose cone is usually fitted to improve earodynamics on the longer straights at higher speeds.
What’s the quality of racing like?
Simply fantastic! The class is tightly controlled in terms of what mods are allowed to increase performance. This means you don’t need to have a wealth of knowledge on what to do to your engine to increase power output, or deep pockets to be competitive. As a result, the karts are all very similar in terms of performance. Typically, the class often produces some of the best racing with a number of karts all jostling for position. If you want proof of how good the racing in 125NGB is, just walk through the pits after a race. The guys are always discussing how good it was with huge grins on their faces.
What about setup and tuning?
There is a bit involved in this and there is a lot of freely available information on various websites on how to do
it. The more experienced members of the club are always willing to pass on some of their knowledge to newer
members as well, so you won’t be left scratching your head for too long. This is often where the most time can be made so it pays to learn the basics and experiment a little at practice days.
The most common setup changes are wheel alignment, jetting and track width. Chassis stiffening bars can also be adjusted. Look for a future article for more detail on tuning a 125NGB Superkart.
Are they expensive to run and maintain?
One of the benefits of the class is overall cost, and it’s for this reason a number of our members choose to stay in the class. They run on Premium unleaded, and the Rotax engine is pretty robust. Rebuild intervals are pretty long with the Rotax manual recommending inspection/rebuild every 50 hours. Some people will opt to rebuild the top end in between these intervals.
Tyres for the class are dictated in the regulations and chosen to improve life of the tyre and thereby reducing costs. As they are basically a slightly modified sprint kart, parts are readily available and reasonably priced.
How fast are they?
Whilst they don’t have gearboxes or the power of the other classes, they will still get your adrenalin running. They will lap QR at less than 1:28 and reach 150kph approaching turn 3.
Sounds fantastic. How do I get involved?
Get in touch with the club and discuss how to join and get amongst the action, or come to a race meet and look at the karts and talk to the drivers. They’re always happy to discuss the joys of racing these little pocket rockets.
There are plenty of second-hand karts for sale that would be suitable for converting to Superkarts, and karts in good condition can be bought for as a few thousand dollars. Now that is real bang for your buck in the motor racing world!
- Visit the Queensland Superkart Club website HERE.