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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: 3dachshunds on January 09, 2026, 06:45:01 PM
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Good evening, I am trying to fix power supply to fuel pump in 1992 k100rs. I frayed wires of float fuel sender while cleaning innards of the tank and troubleshooting no power to pump. So I am getting fuse #6 blown when attempting to start the bike. It appears wires were shorting on ground. So I removed the sender and pried off the white plastic plug from outside the sender to clean corroded terminals with sand paper. Here is my question: when measuring resistance between outside pin of brown wire and tooth where black ground wire to pump negative terminal is, it reads approx 30 Ohms. Do you think there is still continuity of the ground, or should I just buy new sender? I also ruined rheostat while sanding down corroded NiCr wire. It probably could be rewired, if anyone knows parameters of rheostat wire (resistance and total length)
. Thank you. Oh I found why I was not getting power to fuel pump. To embarrassed to admit, but kickstand was up all the time I was trying to troubleshoot it..
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. . . I found why I was not getting power to fuel pump. To embarrassed to admit, but kickstand was up all the time I was trying to troubleshoot it..
The side stand cuts power to the fuel pump when it's down, not when it's up. It's a safety feature designed to keep owners from riding off with the stand down then dumping the Brick when the stand levers the bike off the pavement during a turn.
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I'm working on a fuel sender problem with my MV. From all the reading I've done across different brands, these things happen: senders die. Many manage repairs, but the rabbit hole can be deep for some. Personally, when I rehabilitated my '75s, I just replaced the sender. I kept the original for repair, but of course, life moves on. If I were you I'd just call it a day and get a new one, as I'll be doing the same for my MV after checking all connectors and wires., including main grounds.
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Thank you everybody! New fuel sender arrived from Euromoto and new sender and pump with filter in place. The bike made past just cranking, the engine runs for few seconds as if it was having misfire and dies within second or so. Big progress from cranking only, I hope Inwill get it running just as smooth as my K75!
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Most likely you used up the residual fuel in the line. It's a new pump so fuel must refill the hoses, filter, and pump.
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Once engine turns over the fuel pump starts and "flushes" the fuel system, builds pressure and returns surplus fuel to tank. Unlikely to be "old fuel". More likely that you have an issue with pressure regulator, injectors (could be messed up by old fuel with gunk in it) or injector's control circuit... It's also possible that the hall signal generator is not working, but if it starts for just a little bit that indicates ignition working...
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Got the bike running after cleaning injectors. TBH, I least expected injectors to the culprit. But anyway, I sprayed break cleaner through them while nozzles were open. It was sufficient. I didn’t noticed until now that it doesn’t have stock silencer and it sounds awesome! Next I need to figure out how to reattach mirror. Thank you everyone!