How to get started

The CBR125 Class is one of the official categories of the Hungarian Motorsport Association (MAMS). It’s among the most accessible and affordable classes—one can put together a race bike for just 300,000 to 400,000 HUF. Maintenance is also especially friendly; typically, one set of tires and two oil changes are enough for a whole season.

Riding these small machines is an incredible experience—they’re great for taking corners really fast. The team shows up in increasing numbers at races and training sessions; at some events, more than 20 racers lined up at the start. The community and atmosphere are fantastic, as reflected in the reports. We regularly have exclusive training sessions, where we have the track all to ourselves.

You can view the official technical specifications for the CBR125 category from MAMS here, which outlines the technical requirements for the motorcycle.

At a minimum, the following modifications must be carried out on these bikes:

• Removal of items listed in the regulations (and other unnecessary parts), such as mirrors and lights

• Wiring of components as specified in the rules (e.g., oil drain plug)

• Installation of a lower chain guard (“shark fin”) and a kill switch

• Mounting race footpegs (the stock ones scrape the ground easily in corners)

• Use of slick tires for better grip

• Larger rear sprocket for gear ratios more suitable to track riding

• Thicker fork oil in the front suspension for stiffer damping

  
  

Additionally, these modifications are commonly done:

• Mounting race fairings to avoid damaging street fairings in a crash

• Crash protectors and bar-end guards

• Sport handlebars for better adjustability (based on personal preference)

• Performance exhaust and air filter for increased power

• Carburetor tuning to suit the new exhaust and air filter

Once a motorcycle has been prepared for racing, it can no longer be used for public road traffic, so transportation to track days or races must be arranged separately. These bikes are typically transported by van or trailer. 

Most race tracks offer pit boxes for rent, so if you frequently ride at the same track, it's possible to store your motorcycle there. It’s often worth teaming up with others—since the CBR125 bikes are compact, several can fit into a single box.

The bike

The Honda CBR125R is available used, and you can often find a well-priced example that’s mechanically sound—sometimes the only issue is cosmetic damage to the fairings.

There are three main models:

• JC34 (2004–2006): Carbureted version. These can be found for around 300,000 HUF on the used market. Carburetor tuning can take up to a full day, but many top racers use this model.

• JC39 (2007–2010): Fuel-injected version, which performs reliably across varying weather conditions without needing recalibration. This model is also well represented in the team.

• JC50 (2011–2017): A more modern version with wider rims and a larger fuel tank. Occasionally seen in the field, and some riders use JC50 rims on JC34 or JC39 bikes.

You can find excellent guides on race-prepping these bikes:

• Setting up a Commuterlite Racer

• Oliver’s CBR125 Build Story

Lower Chain Guard Installation

Required by regulations. A simple shaped metal plate will do the job.

Kill Switch Installation  

If the bike doesn't already have one, a kill switch must be installed—without it, entry to the track is not allowed.

Race Footpeg Installation

The stock footpegs scrape easily in corners, so modifications are necessary.

• One solution is to retain the stock pegs and raise them with a custom bracket.

• Another option is to install race footpegs, which offer greater adjustability. They’re relatively affordable, though in case of a slide, they may need replacement—worth keeping spares on hand.

Use of Slick Tires  

For better grip, slick tires are recommended. Most local racers use Dunlop Moto3 tires, which can sometimes be sourced in lightly used condition from professional racers—and they last quite a while on a CBR125. 🙂

Larger Rear Sprocket for Better Track Gearing 

The stock gearing isn’t ideal for track use, so replacements are suggested. The ideal ratio depends on the rider and the track, but a 14-50 setup performs well in many cases. Look for JTF1264.14 and JTR835.50 sprockets, and a 428 JT HDR2 chain.

Thicker Front Fork Oil 

To achieve stiffer suspension, consider replacing the front fork oil with something thicker—experience shows that 20W works well.

Protective Gear

Even in this category, using high-quality protective equipment is essential for rider safety. Basic rules are laid out by MAMS, and before participating in races, equipment checks are part of the technical inspection.

• High-cut motorcycle boots

• Leather racing suit with protectors and reinforced elbows, knees, and spine (one-piece suits recommended)

• Closed helmet compliant with FIM regulations or marked with an E approval, featuring a double D-ring fastening

• Back protector (chest protector is also recommended)

• Motorcycle gloves with protectors that cover the wrist

In addition to the mandatory items, more and more riders are using airbag vests (which require compatible suits) or airbag suits for extra protection.

Insurance is also an important factor. When applying for a MAMS license—or individually—you can request annual insurance coverage. Be sure the policy covers auto/motosport activities, since many “extreme sport” packages don't include this type of protection.