Turn your road bike into a race bike
To road race in the UK with the Auto-Cycle Union (ACU), you must convert a motorcycle into a track-only machine by removing lights, fitting a race fairing/belly pan, lock-wiring critical fasteners (brakes, oil drain), installing a brake lever guard, and ensuring it passes strict noise tests.
But remember, before you want to enter a race you must also obtain an ACU license via a Competitor Training Course (CTC) and Basic Rider Assessment (BRA).
See our check list for getting your ACU race licence further down.
Essential Motorcycle Modifications for ACU Racing
- Belly Pan/Oil Containment: A belly pan (lower fairing) must be fitted, capable of retaining oil in the event of an engine failure. It must have a drain plug (for removing in wet weather races) and be secure.
- Brake Hoses: Must not crossover the front mudguard (e.g. independent lines to each caliper).
- Coolant: Regular coolant cannot be run, but water or race-specific water-based coolants.
- Controls: A brake lever guard must be installed to prevent accidental brake activation during contact.
- Exhaust/Noise: The exhaust must pass strict ACU noise limits (usually 105 dB/A for most classes).
- Horn: must be removed or deactivated.
- Identification: Race numbers must be displayed clearly on the front and sides of the bike, in compliance with ACU regulations (e.g., specific colours for classes).
- Lights & Glass: Remove all road-going lights, indicators, mirrors, and glass/plastic lenses. A solid (i.e. not brake activated) red rain light must be fitted to the rear of the bike for adverse conditions, activated either by a button on the dash or bars.
- Lock Stops: Stops must be fitted to ensure a minimum clearance of 30mm between handlebar with levers and the tank when on full lock to prevent trapping the rider’s fingers.
- Rear Guard: A "shark fin" style chain guard is required to prevent limbs from getting caught in the rear sprocket.
- Safety Wiring: All fluid-carrying components (oil filler cap, oil drain plug, oil filter), radiator caps, and critical brake components (calipers, axle nuts) must be lock-wired to prevent them from coming loose.
Scroll down for a more in depth summary of why lockwiring is important from Bruce Dunn, who is best known for his work in MCN and various bike mags, but has also been a long-term racer.
- Secondary Engine Case Covers: Fitted over existing engine covers to provide a second barrier.
- Tyres: Must be in good condition. Slick tyres and wets are permitted in most club meetings, but check your desired race class to see if they run a control tyre
For more detailed regulations, check out the club and the classes you want to race in. You can see our detailed list of ACU-affiliated clubs here.
Obtaining an ACU Road Racing Licence Checklist
Check out our Guide to obtaining your motorcycle race licence with the Auto-Cycle Union (ACU).
- Join an ACU affiliated Road Racing Club.
- Apply to the ACU for your Novice Licence.
- Get your eyes tested by an optician.
- Book and pass your CTC (Classroom) and BRA (Riding) assessments.
- Prepare your bike for scrutineering (lock-wiring, etc.).
- Enter your first race and wear your orange jacket with pride!
Safety Lock Wiring Overview
Lockwiring is all about safety. More precisely, it adds an extra layer of security that simply is not there when a bolt or nut is left to rely on torque alone.
In theory, a fastener tightened to the correct specification should stay put. If the torque figures are right, and operating conditions are sensible, it ought to resist vibration and heat cycles without any problem. Under ideal conditions, nothing moves.
That is why, if you lift the bonnet on a road car or look over a standard road bike, you will rarely see any lockwire. Production vehicles are designed with generous tolerances and safety margins. They are built to run smoothly, without excessive vibration or extreme temperatures. As a result, the fasteners that hold the engine and chassis together are very unlikely to work loose.
Things change the moment you start pushing beyond normal conditions. Racing and heavy modification are very good ways of doing exactly that.
Once an engine is being asked to make maximum power for long periods, heat and vibration become serious threats to fasteners. Over-revving only makes matters worse. The vibration is no longer contained within the engine. It travels through the frame, while the chassis is also dealing with shock loads that the suspension cannot fully absorb.
Anyone who has ridden hard over the Ginger Hall section of the Isle of Man TT course will understand this instantly. The surface is so rough it can blur your vision. It is no surprise, then, that TT technical regulations require more components to be lockwired than in most short circuit racing series.
If you are racing at an ACU event, certain components must be lockwired as part of scrutineering. Typically this includes sump plugs, oil filters and oil filler caps. The reason is simple. If one of those comes loose, you are not just risking your own engine, you are putting oil on the circuit and endangering everyone else.
Trackdays are different. Lockwiring is not usually mandatory. That said, if you run a dedicated trackbike, it is something that should not be ignored. It is common sense and good practice. The consequences of a loose sump plug at full lean do not care whether you are racing for a championship or just out for a steady session.
In extreme conditions, lockwiring stops small problems becoming big ones. It keeps critical components exactly where they should be, lap after lap, mile after mile.
