Tuesday, May 14, 2013

Adding a "US" generator light in the "proper" location

BMW used the traditional "generator" bulb socket for high beam low beam (to meet Federalization requirements) on later model /2 bikes.  The generator lamp was moved to an auxiliary socket.

I am not sure which models got the generator lamps here. Perhaps someone can comment.

For some reason, Ned's 1968 R69US had no generator lamp anymore and he wanted to restore its original appearance. So I set about devising a method to locate exactly where on the nacelle the US lamp is located.

Location of red generator lamp on a 1969 R69US.

Location of generator lamp in aux location.

The lamp socket sold by Benchmark Works.

The lamp center lies in the tangent to the speedo circumference that is perpendicular to the direction of travel and touching the speedo circumference at its foremost point.

A line drawn from the speedo hole center (needle spindle) through the location on the dial indicating 5 mph is about 26 mm from a point at the speedo hole circumference to the center of the gen lamp hole.

By locating a pencil and turning the nacelle on a flat surface....

...a line is drawn.

The center of the speedo hole was located by placing a ruler and locating the widest point....

...and locating a point on the other line that is 26 mm from the edge of the speedo hole. 

 A compass is set to 8.5 mm, the radius of the new lamp socket.

And the location of the generator lamp is revealed.