Sealed Beam Conversion
Sealed Beam CONVERSION
PETER E. SUTHEIM
WITH THAT ONE HEADLIGHT on your bike, could you swerve just in time to miss a brick lying in the road? Maybe not. Have you compared your headlight recently with lights on cars and on other bikes? Some older machines would be safer with a two-cell flashlight taped to the handlebars.
The vast majority of cycle headlamps use a bulb of some 25 to 35 watts in a parabolic reflector. Properly designed, and kept clean and free of scratches and corrosion, that system can work as well as any. But even a few months of vibration and exposure to moisture and grime can turn the headlight into a flickering yellow candleflame.
American auto manufacturers abandoned the bulb-and-reflector headlight about a quarter century ago. It was superseded by the sealed beam unit, which has two rigidly supported filaments (one for high beam, one for low) permanently sealed with the silvered parabolic reflector in an evacuated glass dish. All American cars use them, but few motorcycles do, since most bikes arc of foreign manufacture.
A sealed-beam motorcycle headlamp is available, though you may have to do some shopping around to find one. I bought one at a large motorcycle dealership. Made by General Electric, sealedbeam units five inches in diameter can be bought in 6 volt or 12 volt types. The 6volt is type no. 4020. (Be sure you get the correct voltage for your bike). Refer to your owner’s manual or ask a dealer if you’re in doubt. Positive or negative ground is unimportant in headlight operation.
Sealed-beam units can be made to fit most bikes of 90 cc displacement and upwards. If your machine’s present headlight is smaller than five inches in diameter, you’ll have to continue searching. You should be able to turn up something either the same size as your original headlight, or slightly smaller.
The following pictures and captions show what needs doing when converting your headlight. The pictures are of a 175-cc Jawa, but the information and the approach apply to almost any machine. ■
