Getting started in Junior Rotax

If you're moving up the ranks, you'll probably already know drivers and parents in this class, and they're always the best people to ask. If you're starting fresh, here's a quick overview of Junior Rotax, sometimes just called Junior Max.

Be realistic

This may sound negative and harsh, but it's the cold truth. If you're getting into karting at this age hoping to race for Ferrari by 20, when most top kids are already moving to F4 with the backing of Red Bull and others, then unless you have a serious budget (I'm talking £100k+ a year), step back and think. If you have that budget, you probably aren't reading this. If you are, talk to the top teams in your class. They'll happily take your money and, to be fair, do a great job with your child. But even then, there are no guarantees.

Karting is great fun and can give a child so much, on a fraction of a top budget. But be realistic so you enjoy it, and do it for the right reasons. No one ever got great at something they weren't passionate about.

Enjoy karting for what it is: weekends away with your child, soaking wet Sundays, drying gloves over the van vents, punching the air because they got 15th in a race they thought they'd finish last. The self-respect they gain from working to improve is priceless. There's a real drive to bring more under-represented groups into the sport, so opportunities may well come. Never say never, but do it for the right reasons. If it's not fun, stop. There are nearly 600 Premier League footballers and only 20 F1 drivers. Buy a football: it's a much easier route!

The class

Junior Rotax is for ages 12 to 16, though most practice days will let you run if you're close to the age range, and a few will let you race if you're on the pace. It uses a full-size adult chassis and a 125cc 2-stroke Rotax engine. Engines are sealed for all Motorsport UK racing, and in almost all independent series too.

JAG recommends a rebuild every 12 to 14 hours, and you can stretch that when you're starting out. It doesn't sound much, but even a full weekend might only add up to 2 hours. If you go once a month, that's roughly every 6 months. Rebuilds must be done by approved JAG engine builders (JAG is the governing body for the Rotax class), and every engine has a logbook recording rebuilds and any work where the seal is removed.

The bare Junior engine is the same as the MiniMax engine. The MiniMax adds a carburettor restrictor, an exhaust restrictor and a different ECU. The only difference between Junior and Senior Rotax is the Senior's power valve, which needs a slightly different cylinder head.

Junior Rotax is quick. VERY quick. Juniors are often faster than seniors at some tracks, and it's probably the most hormone-fuelled competitive class out there. It's also exciting, with some of the best racing anywhere. If your only experience is indoor rental karting, understand this: even the fastest rentals (apart from DMAX) are slower than cadet karts, much heavier, and run long-lasting tyres. You can get away with a bit of contact in a rental kart. Contact in a Junior will probably mean significant repairs to the kart, or worse, to your driver.

So take it steady. But not too slowly, as that causes problems too. More on that later!

Evo or non-Evo?

Browsing Marketplace or eBay, you'll see "Evo" and "non-Evo". What's the difference? It's not a simple answer. As a rule, if it's listed as Evo, it usually is. Non-Evo can cover a lot.

On the engine itself:

• Looks: the Evo has a red top and black crankcase. The non-Evo is bare metal.
• Clutch: the non-Evo drum has visible holes. The Evo has a different clutch and a solid, stronger drum.
• Barrel: non-Evo barrels were cast aluminium and varied a lot. Evo barrels are CNC-machined and all in the same ballpark. This was the major change.
• Gears: plastic internal gears on the non-Evo were upgraded to metal on the Evo.

Here's the thing: almost every non-Evo has had the clutch upgraded, the plastic gears replaced and probably an Evo barrel fitted, which makes it essentially an Evo engine. It'll be advertised as something like "non-Evo with Evo internals", and those engines are comparable.

But that's only half the story. With the Evo, Rotax also upgraded all the ancillaries:

• Exhaust: better flow, and in two parts instead of one
• Loom: more reliable
• Upgraded coil pack
• Battery box, which now holds an ECU
• An ECU controlling timing and the power valve
• Carburettor: far less temperamental and more powerful
• Air box

The ancillaries matter much more than you'd think for running and reliability. A kart listed as non-Evo could be an old engine with old ancillaries, or it could be as good as an Evo. The ancillaries alone cost around £750 to £900, so a kart that's £400 more but has them is well worth it.

"Can't we just get going with a non-Evo and upgrade later?" Sure. But as well as more power, the biggest advantage of the Evo ancillaries is reliability. The jetting range is narrower, so you're less likely to get it wrong, and the electrics are far more robust, so you're less likely to be scratching your head over intermittent running problems. In the right hands a non-Evo can be very competitive, but for your first Rotax, something that starts first time and gets you on track is not to be underestimated.

Chassis

The main manufacturers are OTK, Mad Croc, CompKart, Kart Republic and, more recently, X-Kart. OTK makes several brands that are the same chassis in different colours, including Tony Kart, Alonso, Redspeed, EOS and LN (Lando Norris). Gillard chassis from around 2022 are also OTK. That means parts are interchangeable.

OTK is the most popular, with a huge range of spares and OEM parts, which makes it a great choice for beginners. If you need a spare at the track, someone probably has one. But the year matters: a 2016 Tony Kart is identical to a 2016 Alonso, but a 2017 Tony Kart is different to a 2016 one (the brake caliper was upgraded, for example). Do your research.

Which chassis is best? What's better, a Ferrari or a Lamborghini? Some suit certain drivers better. But OTK is still one of the easiest, performs at the highest level, and spares are cheap and easy to find.

Day one at home with your new baby

The Power Republic YouTube channel is your new best friend. It has great videos on changing everything on your kart. The more maintenance you can do yourself, the better.

Follow these tips before you even try to start it.

Get the right oil

These are high-performance racing engines, made to run flat out on track, not to nip down the shops. You need the right oil. Opinions vary, but I recommend Silkolene Pro KR2, a semi-synthetic oil made for Rotax and homologated for racing. It's much kinder on plugs. Do not use normal 2-stroke oil from a garage or Halfords. It will foul your plug quicker than anything and the kart will stop and refuse to start.

Get the right plug

Denso is the plug of choice for Rotax, from IW24 to IW34 depending on temperature. To start with, don't worry: an IW27 is the one you'll use most.

Starting for the first time

If the kart has been sitting, there's no fuel in the carb. The fuel tank has a small catch tank with a vented lid to keep the pressure neutral. Don't block it, or the engine won't start or will cut out. Put a tube in the top and blow gently to pressurise the tank and push fuel to the carb. Repeat until there are no bubbles coming back. Use the choke to start, and take it off as soon as you can rev it. You only need the choke first thing in the day or after draining the carb, never between sessions.

Once it's running, use one hand on the revs and check the brakes with the other. You should be able to lock them easily. Keep the revs up, and unless you have a reason to run it on the stand, rev it a few times and switch it off.

Before your first day

There's so much you could check, but stick to the basics. Hopefully the alignment is fine, and you'll learn to check it as you get more confident.

Brake cleaner

You'll use a lot of it, so a pressurised refillable bottle is much cheaper than cans. It's great for cleaning, especially carbs. Carb cleaner is a solvent, so only use it on metal away from rubber parts and paint.

Take the carb off and remove the bottom (careful, the floats will drop out). Check the floats have no petrol inside, which causes terrible running. Blast brake cleaner through the jets, then blow through with an air line. There's a 12mm nut on the side with a small filter behind it. Gently clean it with brake cleaner and blow it dry, and refit it with the mesh facing up. It's not a full rebuild, but it prevents 90% of problems. If you're confident, follow the Power Republic videos to rebuild the carb and the fuel pump. It's an easy job and stops those silly first-day problems on an unknown kart.

Battery

Most newcomers don't realise there's no charging system on the kart. All the power comes from the battery, and it's the number one cause of bad running. I often see newcomers finally fix their starting problems, only for the nearly-flat battery to cause more. Charge it fully before the track, and if you can, charge it there too or take a fully charged spare. Use the correct battery: the Yuasa YT7-BS is the accepted standard.

Gearing

Often overlooked on a first trip out. Find out what others run, and add at least 2 or 3 teeth. For example, 12/74 means a 12-tooth front and 74-tooth rear sprocket. More rear teeth give better acceleration. Fewer give more top speed. When starting out you need the revs, so run at least 12/77. Turn up where fast kids are on 12/76 with a 12/72, and not only will you be slow, you won't rev the engine enough, and the plug will foul. You'll even see top drivers pinching their fuel line on the formation lap to stop this happening.

Check the chain tension: about 10 to 15mm of movement.

Your first day on track

Tyre pressures

Different tyres, days and tracks all change pressures, so find out before you go or ask someone at the track. Tell them it's your first day, and most people will give you a starting point. If you really have no help, put 12psi all round and go from there.

First session

You're not going to turn up and beat the local kids, so don't try. Your first goal is to get round a lap. I'm not joking. Depending on the tyres, they'll be like blocks of ice for at least two laps, even for an experienced driver. It's a catch-22: you can't go fast because the tyres are cold, and you need to go faster to warm them up.

Take it steady and the tyres will come in. Start at the back. Build up speed and give it as much as you can on the straights, or the plug will foul, and once it does, it's in the bin. It's fine to brake early and get round the corner safely, but give it some down the straights.

If you can find a track that's open midweek, a quiet session is a REALLY good idea. That's it, you've survived your first session! Go home and sleep. It's harder than it looks! Remember to refuel and lube the chain between every session.

Hopefully by now you've found a few allies in the paddock to help you on your journey. Good luck!