K100 electrical gremlin - K-Bikes.com - Excellence in Motion
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post #1 of 3 (permalink) Old Aug 23rd, 2019, 9:58 pm Thread Starter
Join Date: Aug 2019
Posts: 2
K100 electrical gremlin

I have an issue with my 1989 K100. Bike was running perfect until a few days ago. Riding on highway and throttle stopped unexpectedly and then kicked back in.
Did this a number of times until it finally quit altogether. Got the bike home and I fear I have a ground issue somewhere. I noticed the fuel pump wasn't running when hitting the starter. Tried picking up the tank and as soon as there was movement the fuel pump kicked in. When moved again it kicked out. I fear the tank itself is acting as a ground to the frame. I am thinking this is due to a faulty fuel sending unit as the connector seems to be making good contact underneath the tank. Any help would be greatly appreciated.
bcoe is offline  
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post #2 of 3 (permalink) Old Jan 25th, 2020, 6:21 pm
Join Date: Sep 2008
Location: Honolulu, HI, USA
Posts: 119
Old thread, but my '85 K100RS would occasionally quit at inopportune moments, such as entering the freeway. It drove me nuts until I accidentally discovered that although the main ground wire from battery negative to trans case LOOKED good, there was sufficient corrosion between the wire strands and the crimped connector at the trans side, that it went discontinuous occasionally. Replaced the wire and alles gut!

It's a known problem on K100 bikes, although they are getting a bit scarce, so the knowledge is dying out.
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Honolulu is offline  
post #3 of 3 (permalink) Old Jan 25th, 2020, 11:32 pm
Join Date: Sep 2016
Location: Invercargill, Southland, New Zealand
Posts: 13
Had same with my original K-RT ... on long trip, all OK. Stop for break, ign on & all looking normal - start & all goes out ... & relatively new (BMW!) battery. Can't remember how I swa it - think I was rechecking the battery terminal bolts - but found copper rust in crimp where earth cable went down to gearbox. Wiggled & everything behaving & starting again.

After this ALWAYS added extra earths onto all my Ks (except the K1200 which has it by default finally) - extra earth leads from the battery to all the high current users - starter, alt, frame earth ...
maxfnz is offline  

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