Collection: BA20d Bulbs

BA20D: The dual-beam bulb for motorcycle headlights

The BA20D is a bayonet cap with a 20 mm diameter and 2 offset pins. The associated bulb is dual-beam 35/35W — it combines in a single bulb:

• A 35W filament for dipped beams (low beams)
• A 35W filament for main beams (high beams)

Same principle as the H4 bulb in cars, but in a 12V motorcycle format. Very common on motorcycles and scooters from the 1990s-2010s: Honda CBR, Yamaha YZF, Suzuki GSX, Kawasaki Ninja, some BMWs, modern Vespas.

Lifespan and intensive use of motorcycle headlights

Critical specificity: motorcycle headlights are permanently on while riding (legal obligation since 2004). This means faster bulb wear than in a car — the original BA20D can last 6 to 12 months with daily use.

Recommendations depending on your use:

• Occasional user (weekend) — standard 35/35W BA20D is perfectly suitable
• Daily user (commute) — prefer a long-life (Heavy Duty) with reinforced filament, 2 to 3 times longer lifespan
• High mileage rider or driving school — BA20D LED kit for almost unlimited lifespan

LED conversion for motorcycle headlights

More technical than in cars — precautions:

• Verify that the motorcycle's regulator/alternator power can support the modification
• Choose a CE-approved LED kit ("E" marking) to remain compliant
• For 50cc scooters with a simple dynamo, consult a professional — the electrical system may not be suitable for a modern LED
• For motorcycles with CAN-Bus management (BMW, KTM), choose a canbus LED to avoid dashboard errors