So I had plans to ride my R90S today. Had, because the electrical system was completely unresponsive this morning. Battery is OK so I started to trouble shoot. Check connections, looks for the obvious. Nothing. Eventually I get to pulling the fairing to poke around inside and behind the headlight. This bike has been modified with a Dyna electric ignition so its not stock. I found this connector inside the head lamp. It has a red fuse inside. The fuse has completely disintegrated and there is corrosion on one end. Obviously I need to replace this thing. Anyone recognize the fuse and can recommend a source for parts?
Added Later
So I have figured out the fuse is a Bosch 16a torpedo or continental type fuse on a wire from the diode board to the starter relay. It was not blown, just heavily corroded.
Thanks for the photos. That helps.
• When you say "diode board" you mean the multi-colored connection board in the back of the headlamp bucket. Right ?
• It looks as if the added wire is connected to the RED patch on the multi-colored connection board, which is usually direct from the battery. If that is so, and you are correct about this wire's use, then the starter may work even when the ignition switch is turned OFF. Is that true ?
• Water splashes everywhere on a motorcycle and thus becomes the electrolyte needed for several types of corrosion. If one connector is corroded badly enough to force an open circuit, then we can assume that all the remaining electrical connections within the same headlamp shell are also "iffy". I advise you to buy a product called No-Ox-Id and individually unplug each connector inside the HL and treat each connection, including this fuse holder. This will not only shield it from new water, and help improve the electrical connection, but it will arrest any oxidation or corrosion.
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
So I have not had a chance to continue my troubleshooting.
Yes, the board I am referencing is the multi-colored board inside the headlamp housing.
I''ll try to confirm today but this particular red wire appears to go from that board to the starter relay under the tank. I've never tried the starter with the key off when the bike was functioning normally. Currently there is no electricity going anywhere. It just appress completely dead and unresponsive while having full voltage at the battery and at the other end of the battery leads. Grounds all appear ok so far.
I've thought about jumping this corroded fuse (since it appears non stock). I'll see if that brings the bike back to life. Even if it does I have a fair amount of maintenance due inside the headlight bucket. Lots of corrosion.
Turns out it was that red wire. I snipped out the fuse block and connected then ends. Everything is back to normal. Now I have a better understanding of this beast and discovered some long overlooked maintenance issues to address. So strange how one wire can render the bike completely inop.
I don't have access to an R90S, but I don't believe that fuse is stock. If it's not stock then it was added. If it was added and that's the only way the system works, then by deduction the original power supplying wire is missing, or more probably burned up and removed.
So we might assume a previous owner added a new wire and then thought to add a fuse on that line in case the problem that burned up the original wire returned one day.
I think you DO have a lot of work ahead.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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