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Topic-icon Electrical Gremlin lets talk starter relay

1 year 2 days ago #3278 by Rowdy
Hello friend, first, thank you, no matter what.
1977 R100/7 with sidecar. Bought it running and slowly began to learn about the world of Airheads, no big just really cool, although I hadn’t put any work into this motorcycle personally until this last 6months. Thats when of course I really began to enjoy this motorcycle. Initially, apprx one year ago it had the ferring removed and head lamp relocated to the housing, new tires, a service, clutch rebuilt and some minor things like grips, but nothing else.

When I parked the bike last fall it was running but in very very bad shape and I had no idea. I thought it was needing a carb balance because it was needing to be feathered at stops to keep running but would still go very fast on the freeway (without the sidecar). Well, take note-
Lost keys on the freeway the last ride she was on so it was parked with the key in the run position. Of course I just broke the Earth, but she wouldn’t start again. This is within a few day period 6 months ago that I discovered while trying to start the motorcycle I was dumping so much fuel into the carbs flooding the cylinders so heavily mass amounts of fuel found its way into the crankcase and contaminated the oil either causing or presenting, take note-
fuel diluted oil passing by the shaft grommet behind the points. Wether or not it just needed a competent owner or a fresh points adjustment is not really the issue now. I then began to learn about my machine. I replaced the cylinder seal I believe evenly and correctly replaced the points, changed the oil, gasket, and filter, believing I have done it courtly crush ring and all. I found a possible problem with the swing arm nut nut looking flush on one side and wanted a pro to set the carbs and timing and check it for safety. I thought I was at danger of exploding. Like I said one “begun” to learn about my machine. Well I left it at the dealership in Escondido until they said they didnt hav anyone to work on it. I have it back withe some missing trim and broken parts from leaving it with others but anyway, I dont let anyone touch my motorcycle anymore. I still dont have a key but thought that would be that way for now.
So recap bike ran rough and then no start. Replaced points gap set wide open, replaced seal behind points, and just this last week I;
Replaced the Diode board and mounts, (not the wiring harness) connections looked good, replaced condenser, replaced battery, replaced battery earth cable, replaced voltage regulator, replaced starter relay. Traced all wires and replaced connectors at the neutral sensor, and emergency cut off sensor(?this was directly under the crankcase near the neutral sensor connectors on both sides?) traced all the wires as per diagram in my Chitons and Hines and any spot that was week I cleaned or replaced.
NOW -the alternator harness needs to be changed, its all intact and looks good but when you cut into it its green from one end to the other. But I still dont understand how this would cause my problem. You see I can use my volt meter and see I have a strong fresh wet cell battery of over 14volts. Not knowing if this matters but I left the battery in the machine for three days connected and when I brought in to put on the battery tender not a drop of juice had gone from it. SO new battery and I can find power to the starter relay but not beyond. I think I should be able to find power t the connector leading from the relay to the alternate or wait to the starter cylinoid I think. Im a little off on it right now not having it all in front of me but keep in mind with no key I spent time up there thinking that area had my problem the area up inside the headlight. So Ive tested the key block and found that its in the Parking light switch and not the run switch. I think this because with continuity from the middle post to just 58 post shows parking lights, fun should be the charged inlet posts and then out of the three posts hot not one of the three as in the parking position (im not remembering post numbers off the top sorry) so maybe it was hooked up wrong, still I dont see this causing my problem and I hope I havent frustrated you. The problem is still a no start but a no start dead dash and just zero nothing.
Back to it I have power to the starter relay and ive replaced it with a new one and there is no power coming from it. This is where im stumped. Yes I need to have it keyed but is that my problem that from power to come from the relay it has to be called on. That doesnt make sense to me a switch is either open or closed right. There isnt a open switch that closes and tells another open switch (relay) to close, with what charge would it use to send the im closed signal. See im choked up. The turn signal relay is in bad cracked condition but no relation right, I even though the headlamp relay might have something to do with it but being that I cant test for any electricity passed the starter relay im stumped and have a hard time believing I received a faulty relaxin the mail but oddly enough very strange to me in my Chiltons maculal it says the starter relay is a component that cannot be checked or tested, if its suspect replace it. Well I did and im still looking at it crooked. What do you think Pal?Thank you!!!!

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1 year 1 day ago #3285 by Wobbly
Replied by Wobbly on topic Electrical Gremlin lets talk starter relay
Just exactly where would you like to start ? :P

Just to start off.... You did not dump all that fuel into the intake and flood the oil supply while trying to start the bike. That happened over a long period of time, maybe 24 hours or more. You need to 1) replace your float needles in both carbs, 2) replace the rubber packing inside both petcocks, 3) perform a complete engine oil and filter change, and 4) teach yourself to turn OFF the fuel whenever and where ever you park the bike.

If you find small pieces of fuel hose stuck in the float needle seats, then replace all the fuel hose too.

Next !

Don't hide 'em, Ride 'em !!

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1 year 1 day ago #3288 by Rowdy
Replied by Rowdy on topic Electrical Gremlin lets talk starter relay
thank you, Im sorry I forgot to mention that the floats, (not jet though,) and fuel lines are 6 months new, and have already changed fluids, gaskets, and filter. Although, none of those remotely adress my current problem at the stsrter relay. but thank you for that information.

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1 year 1 day ago - 1 year 1 day ago #3289 by Wobbly
Replied by Wobbly on topic Electrical Gremlin lets talk starter relay
Rowdy -
It's too much information for my poor old brain to sort out. 1977 R100 /7 with starter issues, we got that much !

Just give us the complete problem description in 4 concise sentences. Thanks.

Your concept of the BMW electrical system seems to be very confused. There are 2 separate electrical paths dealing with the "starter"....
• Power created by the alternator travels to the battery via the large gauge wire going between the starter motor and the battery.
• Power consumed by the accessories (lights, ignition, turn signals, etc) pass from the battery through the Starter Relay on their way to the ignition switch on a much smaller gauge wire.

Don't hide 'em, Ride 'em !!
Last edit: 1 year 1 day ago by Wobbly.

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1 year 19 hours ago - 1 year 19 hours ago #3291 by 1872
it seems you have thrown a lot of money into this machine, some of which was probably unnecessary. Judging from your choice of dealers I guess you are in California. A call to your airmarshal as listed in Airmail would be a good place to start. He should be able to connect your with a nearby Airhead willing to take a look. March 17 is a rally in San Diego this would be a good place to go even if the bike is not running.
It will be more productive, not to mention much cheaper, to have an experienced person looking over your shoulder while trouble shooting than to continue in the direction you are going.
Leaking carbs normally overflow onto the ground but yours did not. Fuel tanks can be contaminated with dirt which will cause float needles to stick open. There are filter screens in the tank, but they may be missing or contaminated.
Good luck in your airhead repair.

Last edit: 1 year 19 hours ago by 1872. Reason: cocorrect spelling

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