I have fiddled around with this connector all season. Until two weeks ago. Out on a long ride 150km from home, in dense traffic the bike quit. Had to push it over two lanes to the shoulder. It was that connector.
The issue was the female part of the connector was pushed back not making contact with the pin.
Pictures show the cure a 4 pin connector from eting bought on amazon.
I hope this will help others avoid my experience!

Another option is to use a four pin flat trailer wire connector. Its wire colors are green, white, yellow and brown which works nicely with the stock wire colors.

Deutsch connectors. After a fight with a damaged wiring harness on an H-D 1200 Sportster last weekend, my garage floor has a scattering of the orange waterproofing seals that I haven't yet been bothered to sweep up.

The bike lost, BTW. It went home with a fully-working wiring harness.

Plenty of OEM connectors are available here: https://q-tech-shop.de/en/c/connectors?sort=position-asc&page=7

I've just fixed my old wires and connector by replacing them by a Peugeot J5 wire, originally dedicated to internal lighting. Plug and play, with a much more thick wrapping.
Cooked under the tank for years, the wires were naked.Apart from the place where the coat broke, they were absolutely rigid.

Oof! Some of those prices are horrific. These for example:

https://q-tech-shop.de/en/p/connector-for-fuel-injector

Compare to a seller on ebay that I use a lot:-

https://www.ebay.co.uk/itm/141725774390

Just a few Euro cents more gets you a full set of four. I'm assuming the P&P to France would be about the same from both Germany and the UK, but I could be badly mistaken on that. Then, of course, there's the VAT problem and Customs to take into account.

Postage and VAT are not the problem to ship from non-UE countries o France. It's anyway the same price that I'd pay when buying from inside UE.
But the delivery company who collects the VAT and, depending on the case, the customs taxes is selling this service a very high price.
Imagine buying these 4 injectors connectors:
7,75£ is 9,15€
Plus 3,50£ for delivery is plus 4,13€
So 13,29€.
There are no custom fares from UK but VAT: +20%
So 15,948€ (you can ask a refund for this)
The delivery company charges 16 to 17€ to collect VAT, whatever the amount is...this "service" doubles the price for small amounts like this, at aprox.32€ (28 with a TVA refund). You don't pay? So there's no delivery.
Theoretically you should be able to declare and pay yourself VAT, but it's almost impossible unless you carry your own goods at the physical border, or you are a company with huge VAT amounts to pay. Most of public offices are closed to individuals.

If I buy at Q-Tech, I'll pay the 4 connectors 23,26€ delivered.

I used to buy (and sell) a lot of parts in UK, trading with Motorworks, Motobins, and Hitchcocks motorcycles.
I don't do no more since Brexit.

jbt wrote:The delivery company charges 16 to 17€ to collect VAT, whatever the amount is...this "service" doubles the price for small amounts like this, at aprox.32€ (28 with a TVA refund). You don't pay? So there's no delivery.

Yes. There's been a couple of times that I've left an ebay order to rot rather than pay £19.00 for someone to collect a £0.50 VAT invoice, where that £19.00 exceeded the cost of the item + VAT.

Since you guys are talking about the plug replacements, I’m
Just about to replace the plugs for both my k100 and k1100
The cable of the k1100 is rock hard, so I like to change that as well.
(I mean the cable coming from fuel sender to plug)

Anyone any hints on the white (yellowish) plastic cover on the fuel sensor, how to remove/open this, so I can (sort of) re-use it ?

Btw - to make my life easy, I bought 4pin deutch connectors that are pre-wired.

You can't replace the plastic covering on the fuel sender. Where the wires go through it's sealed with an epoxy-type filling; digging it out isn't difficult but ensuring the that replacement epoxy is leakproof is pretty much an insoluble problem. Your best bet is to:

- cut the wire about four inches from the tank exit
- carefully remove the outer cover until the four wires are exposed
- cut the exposed wires again so that they are staggered by about 10mm to each other
- match up the stagger on the wires with the Deutch connector
- slide individual pieces of heatshrink down the Deutch wires
- strip and solder the wires together
- cover the joints with the heatshrink
- finish off with self-amalgamating tape to make a solid waterproof cover from the remains of the OEM cable to the new connector. Don't use insulating tape because it will eventually unpeel and piss you off.

MartinW: didn't you do something smiliar?

Dai I just cut out the OEM connector as close as possible to the connector. I then fitted a waterproof  Automotive connector from the local electronics store. The wires were long enough for the new connector to be fitted without soldering in additional wire.
Regards Martin.

Thanks guys. Let me remove the black outer cover and see what I find.
Currently I can’t even bent the wires (without some force that is) hope that’s the cover then, not the wires. What you described Dai was my original plan - but if the wires are toast I might have to go that one step further. Thx again!

Finito

I used a waterproof marine connector on my K100. Looking back I now realize that the fuel pump I replaced with only 8 thousand miles on it was probably good. It was drawing close to 10A on a 7.5A circuit. I blamed the pump but after I put in a new one that 4-pin original connector caused me to die on the road. After replacing it with the marine unit I checked the current draw and it was right where it was supposed to be. This was over 2 years ago and it's been fine ever since. I saved the old pump as a spare to travel with. This tool is a must-have for these bikes:
Fuse Buddy Tool

Regarding post14 by yamaguzzi: The Fuse Buddy Tool attached in your post looks interesting. I get that it tests fuses rated up to 20 amps, but fuses come in a number of different sizes. Is it a universal size tester in the up to 20 amp range or does it only test one size/type. The various ads online are unclear. Could you clarify please. Thanks.

Interesting tool, I might need to get one myself!

If you look at the picture on Amazon link, you see there is a fuse in the plug that goes into fuse holder (of the bike) - so you can put in any fuse (up to 20A)

redrockmania wrote:Regarding post14 by yamaguzzi: Is it a universal size tester in the up to 20 amp range or does it only test one size/type.

The 302M Fuse Buddy is designed to test up to 20amp mini fuses, according to this source.

If you're a wiring masochist like I am, this is an interesting page: https://www.esitest.com/C/17/FuseBuddy. There's a standard fuse tester on the page.

Thanks Laitch and Dai - your attachments clarify the basic tester only tests Mini Fuses, but some of the enhanced testers on offer come with outboard connectors allowing different types (physical sizes) of fuses to be tested.

redrockmania wrote:Thanks Laitch and Dai - your attachments clarify the basic tester only tests Mini Fuses, but some of the enhanced testers on offer come with outboard connectors allowing different types (physical sizes) of fuses to be tested.

There are options…you can buy one for mini fuses, one for regular size automotive fuses (pictured) and as redrockmania says, some kits have an adaptor that allow the regular size fuse holder to test mini fuse circuits.

And on the subject of fuel pumps, when I resurrected ‘Heidi’ from an off road lay up period (2019-2024), I found the (original 33 year old?) fuel pump was not working. To avoid the black gunge problem caused by leaving stagnant fuel in the tank, I had carefully drained all fuel during lay up preps. What I hadn’t counted on was the internals of the pump corroding (moist seaside air) and preventing it turning easily (or drawing a very high starting current). High starting currents going through, old, original wiring with age hardened and increasingly brittle insulation is not very desirable either!

Following a previous fuel pump failure (while riding), I destructively examined that pump…it’s not designed for internal repairs…and found a lot of corrosion on the steel components of the rotor that made it very stiff to turn. I attributed this to water in the fuel (and of course, water will naturally accumulate at the lowest point of the tank if it separates out from the fuel i.e the fuel pump sump).

My lesson learnt was that regularly riding will keep the pump spinning and minimise the build up of corrosion products. If laying up a bike for an extended period, completely empty the fuel tank and remove the fuel pump. The pump can be liberally dosed with wd40 or suchlike and stored in a ziplock bag until the bike is recommissioned. I also recently bought 2 new fuel pumps from eBay (£45 for the pair) and now carry one on the bike as a spare. Easy to change at the roadside and quicker than waiting for a recovery truck!

Born Again Eccentric wrote:And on the subject of fuel pumps, when I resurrected ‘Heidi’ from an off road lay up period (2019-2024), I found the (original 33 year old?) fuel pump was not working. To avoid the black gunge problem caused by leaving stagnant fuel in the tank, I had carefully drained all fuel during lay up preps. What I hadn’t counted on was the internals of the pump corroding (moist seaside air) and preventing it turning easily (or drawing a very high starting current). High starting currents going through, old, original wiring with age hardened and increasingly brittle insulation is not very desirable either!

Following a previous fuel pump failure (while riding), I destructively examined that pump…it’s not designed for internal repairs…and found a lot of corrosion on the steel components of the rotor that made it very stiff to turn. I attributed this to water in the fuel (and of course, water will naturally accumulate at the lowest point of the tank if it separates out from the fuel i.e the fuel pump sump).

My lesson learnt was that regularly riding will keep the pump spinning and minimise the build up of corrosion products. If laying up a bike for an extended period, completely empty the fuel tank and remove the fuel pump. The pump can be liberally dosed with wd40 or suchlike and stored in a ziplock bag until the bike is recommissioned. I also recently bought 2 new fuel pumps from eBay (£45 for the pair) and now carry one on the bike as a spare. Easy to change at the roadside and quicker than waiting for a recovery truck!

Regular riding is key to keeping anything in good condition. When I got my 88 K100 it had been sitting indoors in a dry basement for 15 years with a full tank of gas. It was a mess. Rust and brown slime everywhere. I took it all out then washed the inside of the tank with soap & water. After the soap and water, I used muriatic acid and the inside of the tank was like new. Then all new parts from the fuel pump down to the injectors which I soaked in fuel injector cleaner for a few days.Hoses, clamps, pressure regulator fuel filter, fuel level sender. It was all like new before I ever even thought about trying to run it. This it what's required after an improper long-term layup and well worth the effort