Which bulb should I choose for my motorcycle or scooter?

Replacing a bulb on a motorcycle or scooter is straightforward — as long as you know the right base, the right voltage and the right type of lighting. This Pharos Boutique guide helps you choose a type-approved, reliable and long-lasting bulb for your two-wheeler, whether it is a recent model or a classic.

1. Identify your motorcycle bulb base

The base is the part of the bulb that fits into the reflector or socket. It is the first compatibility criterion: a bulb with the wrong base simply will not fit. The most common ones on motorcycles and scooters are:

• H4 (P43t): the most widespread headlight base, with a double filament (low beam + high beam).
• HS1 (PX43t): very similar to the H4 but specific to many scooters and motorcycles — be careful not to mix them up.
• H7, H1, H3: found on some sports bikes or twin-headlight models.
• BA20d / BA21d / P45t: headlight bases for classic and vintage motorcycles.
• BA15S, BAY15D, BA9S: for tail lights, brake lights, indicators and sidelights.

If in doubt, remove the old bulb and read the marking engraved on the base or glass, or check your motorcycle's manual.

2. 6 volts or 12 volts?

The voltage is crucial: fitting a 6V bulb to a 12V circuit (or vice versa) will cause the bulb to blow immediately or fail to light correctly.

• 12V: almost all modern motorcycles and scooters.
• 6V: vintage motorcycles, mopeds and classic mopeds. Pharos Boutique offers a dedicated 6-volt range for these vehicles.

3. The headlight (low and high beam)

This is the most important lighting for your safety. On most two-wheelers it is an H4 or HS1 double-filament bulb. To ride at night or in bad weather, choose a R37 type-approved bulb with a steady light output. For intensive use, the Longlife / Heavy Duty range offers greater service life and better resistance to vibration — a real advantage on a motorcycle. Browse our motorcycle & scooter headlight bulbs.

4. Tail lights, brake lights and indicators

To be seen clearly, do not overlook signalling. The BA15S (single light), BAY15D (dual-intensity tail/brake light) and BA9S bases fit most tail lights and indicators. An amber bulb is often required for indicators with a clear lens. See our motorcycle signalling bulbs.

5. Dashboard and sidelights

The small instrument, dashboard and sidelight bulbs (BA9S, W5W, T5, festoon bases) light up your gauges. They are inexpensive but essential for reading your speed and warning lights at night. Discover our dashboard and sidelight bulbs.

6. Halogen, LED or xenon effect?

Three main families are available:

• Halogen: the original standard, reliable and economical, fully type-approved.
• Xenon effect / Super White: a whiter light and a modern look, while keeping a halogen base.
• LED: more energy-efficient and very durable, ideal for signalling; for the headlight, check your vehicle's compatibility and approval.

7. R37 type-approval, your guarantee of safety

All Bosma bulbs supplied by Pharos Boutique are tested for their service life, light output (lumens) and colour temperature, and carry the European R37 type-approval certificate. That is your assurance of compliant, safe lighting that will not let you down on the road.

Frequently asked questions

What is the difference between an H4 and an HS1 bulb?
They look alike but are not interchangeable: the HS1 is specific to many scooters and small motorcycles. Always check the marking on your original bulb before ordering.

Can I fit an LED bulb in my motorcycle headlight?
It is possible on many models, but compatibility (reflector, beam pattern, approval) must be checked. For signalling, however, LED is an excellent choice.

My bulb keeps blowing — why?
Most often because of vibration or an unsuitable voltage. Choose a high-resistance Heavy Duty bulb and make sure the voltage (6V/12V) matches your motorcycle.

A question about a specific reference? Our advisers will help you find the exact bulb for your motorcycle or scooter. Discover the full Motorcycle & Scooter Bulbs range.