1985 K100RS dodgy fuel pump 4-pin connector.

Yesterday while out for a ride my bike suddenly quit. I had a pretty good idea why and was right. After popping off the left hand side knee pad trim, unplugging and plugging in the 4-pin female connector to the fuel pump, I was on my way without further incident. This is the 2nd time this has happened although the 1st time was in my garage, not on the road. I had previously sprayed it with electrical contact cleaner, followed up with dielectric grease.

When I got home I unplugged it and using some hobbyists micro-tubing, slid it over the female pins, collapsing them slightly. I sprayed male and female pins again with cleaner and dielectric grease. It did fit tighter, however, I would like a long-term solution. I have the early-style connector so was wondering what some of you guys have done for a permanent solution.

Thanks,
Tom

You can just replace the connectors with something else, or if you want to maintain originality you can replace the pins in those housings. I think I have new pins for that style.

I would just replace them with the Oilhead style because I have bajillions of those housings and pins. But if you replace a fuel tank or gauge you will have to deal with the mismatch.

When this happened on my K100RS, I used a pointed pick to slightly close the gap on the female pins to engage more firmly. That had to be 10-15 years ago and haven't had to touch it since.

Frank

Back in the 1990s when Old Smokey (K75T) had only about 200,000 miles on it I started having this issue. After repeated attempts to make the connections more secure I just transplanted an ordinary four-pole trailer connector I got at an auto parts store. Not exactly an elegant solution to a purist, but by then the bike had an 8.5 gallon gas tank coated with truck bed liner, a solo seat, and a Harley FLH trunk so an inauthentic tank connector was of little matter.

I just found this on Tills website. This looks like it.

I chased the same problem

I chased it for quite a while before I discovered the faulty fuel pump connector. I went out and got a GM style water proof four pin connector and solved the issue in about 20 minutes.

I replaced mine with a 4 pin trailer light connector. Just cut and splice the wires with heat shrink connectors.

eastbay said:

I replaced mine with a 4 pin trailer light connector. Just cut and splice the wires with heat shrink connectors.

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And this will fit the plug with the male pins on the underside of the tank?

mcmlcccvrs said:

And this will fit the plug with the male pins on the underside of the tank?

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My guess is you would need both sides. If I change (critical) connectors, I use these-



They are called " Deutsch connectors " and are a bit fussy to install but should be the last time you need to mess with that. There are instructional videos on Youtube on how they go together. Pacer Group has them- https://www.pacergroup.net/products/terminals-and-connectors/deutsch-connectors/dtp-series/ and they are now available many places.

OM

"Deutsch" is just the brand name, and they make many different kinds of electrical connectors, but that type of connector is their DTP series.

Pauls1150 said:

"Deutsch" is just the brand name, and they make many different kinds of electrical connectors, but that type of connector is their DTP series.

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I was just hoping it would help
OM

Got that, no biggie... but we can't just walk into the local FLAPS and say "Hey, do you have any Deutsch connectors?" ... They make thousands!

Handy household hint - If one doesn't have the expensive specific crimper for the pins, a small needlenose pliers and some careful patience can fold the tabs over so the pin fits into the socket; this can be preferable to just cutting the tabs off and soldering the wires, because any solder overflow may get on to the shoulder of the pin and prevent it from seating in the shell properly.