Engine shuts down when I switch the lights on

[1955fle]

I have a stock '55 FL that has started shutting off when I switch on the headlight. It has been running great and only started recently doing this. Bike runs fine with switch is 1st position. When I click over to the second position it shuts the motor off. The headlight comes on at this point. Is this a bad switch (this is what I am guessing), or a short somewhere? What is the best way for me to test this? Any help would be great.

[awander]

It certainly could be the switch-it may be sending voltage to the headlight, but not to the coil.

It could aslo be that the charging system is not working properly, and the extra current draw of the lights causes the engine to misfire. i don;t think this is so likely at idle, but it's possible.

If I were you, I would put a voltmeter across the battery terminals and see what it reads before you star-should be a little over 6V-then start the bike and see what the meter reads at idle, and also with the engine running a bit faster-you should see a higher voltage here than you did when the bike was not running.

Finally, switch the lights on and see what kind of voltage reading you get. If the bike dies, then pop the cover off teh ignition timer, and see if the voltage reading changes when you open and close the points.

Finally, put the meter on the coil and see what you read, both points open and points closed. If there is voltage getting to the coil, then you should read about 6V on bothe sides of the coil with the points open, and 6V on one side, and 0V on the other side when the points are closed.

If you read 0V on both sides of teh coil, with the points open or closed, then suspect the switch or the wiring from the switch to the coil.

[1955fle]

Thanks Andy. This will give me somewhere to start. I will let you know how it goes. -Carl

[Panacea]

When mine does that, I spray a little WD-40 on the switch contacs, then the lag time with no juice between contacs is less so the motor won't kill....Mike

[1955fle]

I tried cleaning the contacts and that did not work. This is an aftermarket switch made in Japan. It has lasted for 8 years but I would like to replace it with a better quality version. Does antone know where I can get an original with keys? I know it is asking a lot.

[panhead]

I bought one from Eastern if I remember well.

[1955fle]

Do you have any contact info for Eastern?

[panhead]

It's from Dixie Distributing Co., part no. RPLS71500-36

[1955fle]

I contacted Dixie Dist. and they only sell to dealers and could not tell me where the part is made. I may have to keep looking.

[1955fle]

Well I think I solved my problem last night. I took the switch apart and noticed one of the terminals was loose. I tightened up the rivet and the problem went away. Much brighter lights and runs fine. Thanks for all of the input. -Carl