After rebuilding my Bosch started and replacing the solenoid, I accidentally shorted the positive terminal from the diode board on the Moto Guzzi relay terminal on the new solenoid and now I have a starter gremlin. I have since fixed the offending cable and terminal and replaced the Diode board, voltage regulator and starter relay. The issue is this...When I turn the key, I have dash lights, no headlight, no blinkers and no horn. The kill switch does make a relay I installed years ago as a trigger for a light switch and that is connected to the rear brake lead. The starter button does nothing. The battery is fully charged and showing 12.9V. After reading the Clymer manual and following the schematic I have narrowed the issue to the Ignition switch. The fuses are good but I measure no voltage on either side with the ignition switch turned on and the kill switch in the run position. The image below shows the route of the power and notice how the fuse seems to run all of the items affected. I have done my due diligence in troubleshooting and feel I have isolated the issue. But, before I spend $165 for a switch, I am just needing a 2nd opinion.
• First of all, I don't understand "Moto Guzzi relay terminal". Are you saying it's "like a Moto Guzzi", or that you've installed Guzzi parts on your Airhead, or that I'm on the wrong forum ? Some help, please.
• Before you spend $165 on an ignition switch, you need to diagnose your issue properly, not simply replace parts. You'll need the correct tools to do this and the tool of choice is a mechanic's test lamp. Commonly available at any auto parts store or on Amazon.
The objective is not to measure the electrical power, but merely to test for the presence of electrical power. Therefore, troubleshooting goes much faster with a lamp than a meter. Power, stored in the battery, has to complete a loop or "circuit" in order to do useful work. One side (the Negative polarity) is connected to the engine and frame, the other side (the Positive polarity) is insulated from the engine and frame. So we take the alligator clip on the test lamp and connect it to a fin on the aluminum cylinder head. By doing this, anywhere we find a Positive polarity will illuminate the lamp inside the handle. Start by probing the battery Positive (+) terminal on the battery.
• Electrical power follows a linear path through the system. The schematic is the "road map" of that flow. We want to test in a logical order because electricity flows in a logical order. You'll absolutely take longer (i.e. waste time) by jumping around, than to follow the path indicated by the schematic.
- The schematic says a RED wire takes the power from the battery to the ignition switch. (We already tested the battery.) So stick your probe onto the RED terminal on the rear of the ignition switch. Is power making it to the ignition switch ?
- The schematic says power comes out of the ignition switch on GREEN (for ignition and starter) and GRAY (for lights). With the ignition switch in the proper key positions, probe both those for the presence of electrical power. Is power making it out of the ignition switch ? If so, then the ignition switch is good.
- From there the schematic says the GREEN goes to one of the fuses. Find the fuse connected to a Green wire. Probe the Green wire going into the fuse. Does it test OK ?
- From there the schematic says the power comes out of the fuse on GREEN/BLACK. Probe the Green/Black wire coming out of the fuse. Does it test OK ?
- And the testing continues in this fashion until you find power going IN with no useful work coming OUT of that device. Be sure and mentally segregate the components you test, because some of them like Switches and Fuses simply pass electrical power through, while devices like Lamps do useful work you can detect.
Additional Notes
► Realize that the electric starter system is not nearly as simple as you describe. There are safety interlocks involved. 1) The bike MUST be in neutral OR 2) the clutch lever has to be pulled in... for the starter to be allowed to activate. Both the neutral switch on the bottom of the gearbox and the electrical switch at the clutch lever are 2 electrical switches that fail all the time. Have those been tested ?
► This bike is quickly approaching being 1/2 century old !! How many 1978 automobiles dis you see on the road today ? Proabably zero. Sure your bike has a lovely exterior, but that does not mean that every piece inside is just as spotless as the day it rolled off the production line. Due to 45 years of water out on the highway and in wash bays, the brass electrical terminals have started to corrode. Over the course of decades many of these electrical terminals and contacts are no longer properly conducting electrical energy. Therefore, I highly suggest that each terminal, connector, fuse, relay, switch, (whatever) that you disconnect >> for whatever reason << be coated with a tiny amount of electrical contact anti-oxidation compound, such as No-Ox-Id by Sanchem, before being re-connected. This will eliminate the microscopic electrical issues you cannot see. Link HERE.
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Also read....
https://www.airheads.org/community/my-airhead-needs-help/1975-r60-6-wont-start/#post-15259
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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