Procedure for Aiming Motorcycle Headlights

A motorcycle's low-beam headlight should not blind other motorists.

A motorcycle's headlight is vital to riding safely at night or in low-light situations, illuminating possible road hazards and alerting other motorists to the motorcyclist's presence. Most motorcycle's headlights are not aimed properly, a problem that can make night riding a dangerous proposition.

Reasons to Adjust the Headlight

A motorcycle's headlights undergo constant vibration during a ride. The headlight can gradually move out of position over time, changing the way the headlight illuminates the road ahead. A misaligned headlight can also pose a hazard to other motorists, temporarily blinded by a stray headlight beam. In fact, a headlight beam aimed above certain vertical heights is a violation of the traffic codes used by most states. Simply put, taking the time to re-aim the headlight will ensure a safe and pleasant ride for both yourself and others.

Headlight Aiming Preparation

Checking and adjusting a motorcycle's headlight aim requires a few measurements and a large, light-colored wall. Support the motorcycle in an upright position, then measure the distance between the floor and the center of your motorcycle's headlights. Place a strip of tape, or draw a line, horizontally along the wall at the same height as your headlights. Place a second line two inches below the first mark to measure the headlight's low-beam function. Create a vertical mark running between the two horizontal marks to adjust the headlight's side-to-side aim, using a strip of tape. Finally, park the motorcycle facing the wall at a distance of 25 feet. Place the motorcycle in a locking wheel chock, or have an assistant support it in an upright position during the headlight aiming and adjustment procedure.

Aiming the Headlight Beams

Turn the motorcycle on and activate its low beam function. Ideally, the upper edge of the headlight's low beam projection aligns vertically with the wall's lower mark and horizontally with the centerline. Activate the high beam after checking the low beam aim. Again, the upper edge of the high beam projection must align with the upper horizontal mark and the vertical centerline. Adjust the low or high beams, using the headlight adjustment screws, if either beam is misaligned.

Adjusting the Motorcycle's Headlight

Adjust your motorcycle's headlight aim by physically repositioning the headlight assembly, as is the case for some cruiser-style motorcycles or by using a set of adjustment screws to reposition the headlight lens or reflectors. Loosen the headlight assembly's mounting bolts with a socket wrench to reposition the headlight's low beam until it is aligned with the lower mark and the center line, then tighten the mounting bolts. The adjustment screws used by most motorcycles are typically found behind the headlight assembly and come as a pair to control horizontal and vertical aim. Motorcycles equipped with a dual-lens headlight will have four adjustments screws, two for each lens. Use a screwdriver to turn the screws until the headlight beam aligns properly with the corresponding marks on the wall.

References

• "Haynes Motorcycle Workshop PracticeTech book"; John Fidell; 1999
• "The Professional Motorcycle Repair Program"; Professional Career Development Institute; 1995
• "Headlight Aiming Explained"; Motorcyclist Magaine; February, 2009
• "Honda CBR1000RR Service Manual"; Honda Motor Co.; 2006
• "Harley-Davidson Service Manual: Softail models"; Harley-Davidson Motor Co.; 2004