How to release fuel injection plug on K75S?

[Shel]

Hi folks,

I'm new here today and have done my best to read posting rules and search from a solution to my problem.  I did find a post on removing the K75 battery, but all links to the photos are dead now. 

I'm having problems releasing the plug for the fuel injection control unit on my 1993 K75S in order to pull the battery out.  The old beast has been garaged since 2009 and I'm considering replacing it with an older '70s vintage BMW that's a bit less top heavy and easier to handle.  I just don't have the strength anymore to handle its weight and high center of gravity.

According to the manual you insert a screwdriver blade through the hole in the base of the injection module tray above the battery and press it forwards.  The arrow in the diagram shows the plug sliding out to the left side of the bike. Here is the page from the instruction manual:



And here's the hole in the tray where you can see the top of a metal fastener of some kind that's attached to the wiring harness end of the plug:



I'm dropping the screwdriver blade down through the upper right corner of that photo, and then pressing the top of the screwdriver towards the right side of the bike, pivoting the shaft on the plastic tray and pushing the plug out towards the left of the bike.  I can see that the tip of the screwdriver is lowered below the plug when I look from underneath the module from the side of the bike.  But the plug just doesn't budge.  I thought I might need to release the catch on the forward end (steering forks end) while I'm leveraging the back with the screwdriver:





But from what I can tell, that catch should release as the rear end of the plug pivots out of the injection module.  Here's the side view of the plug and module.  I slid the zip tie to the right to see what it wrapped around:



And this shows the bottom of the metal fastener on the wiring harness end of the plug:



I'm guessing that will stay in place as the plug pulls away from the module.

Thanks for any input on getting this plug disconnected.  My signature is not showing up in the post preview, so forgive me if it's duplicated below,

Shel
'93 K75S
SoCal

[Shel]

Here's a couple photos of the bike.

[Chaos]

Nice looking S, hope it finds a good home.  Take this Phillips head screw out, my memory is a little foggy but that should easily let you pull the plug after releasing the plastic catch.

[Shel]

Nice looking S, hope it finds a good home.  Take this Phillips head screw out, my memory is a little foggy but that should easily let you pull the plug after releasing the plastic catch.

Thanks for the suggestion.  I just tried removing that screw, but it had no effect.  The rear end of the plug just doesn't want to budge.  It is a nice old S for sure.  I was very lucky to have had 3 owners before I bought it 2005 who kept it in superb condition.

[Laitch]

Two things you must do. Locate the heavy wire connection on the right side of the plug then move the wire outward slightly, if necessary, so it can clear the frame. After that, push the latch to the Right with your screwdriver as illustrated in the attached photo then pivot the plug on its hook by swinging it outward pulling on the wire that you positioned to clear the frame, then unhook the plug.

[Shel]

Two things you must do. Locate the heavy wire connection on the right side of the plug then move the wire outward slightly, if necessary, so it can clear the frame. After that, push the latch to the Right with your screwdriver as illustrated in the attached photo then pivot the plug on its hook by swinging it outward pulling on the wire that you positioned to clear the frame, then unhook the plug.

That did the trick Laitch.  I tracked down my Clymer's manual, and it said to move the top of the screwdriver towards the FRONT of the bike pivoting on the plastic hole and causing that top of the latch to move towards the BACK of the bike, or right as you pointed out.  Not pressing the screwdriver towards the right side of the bike as the K75 owners manual indicated.  I thought I was just going to pry the rear end of the plug with the wiring harness out of its socket.  But It turns out that that shiny metal latch slides in and out of a catch on the plug.  I levered the screwdriver and pulled on the wiring end of the plug and it came right out.

Here's the entry in the Clymer's manual:



I have the battery out and charging now.  Thanks for you input Laitch. 

[K1300S]

Manual is actually correct, also.  It means move the whole screwdriver to the rear, not pivot it to the rear.

[Shel]

Manual is actually correct, also.  It means move the whole screwdriver to the rear, not pivot it to the rear.

When you insert the screwdriver through the hole and move the top in any direction, it's going to contact the edge of the plastic hole.  The center of the screwdriver shaft will pivot against the side of the hole causing the blade end of the screwdriver to move in the opposite direction.  Yes, you could grab the screwdriver more forcefully and keep it from hitting the edge of the hole.  But I'm pretty sure neither manual, owners or Clymer meant for you to do it that way.

The owners manual says:

• Insert a screwdriver blade through the hole (arrow) in the base of the tray, press it forwards (arrow) and release the catch (4) on the multi-pin plug (5) for the fuel injection control unit (3).

If you look at the diagram in the owners manual and compare that to Clymer's instructions and diagram, it's pretty hard to interpret them as meaning the same thing as far as how to move the screwdriver.

[lmiklosy]

Shel:   It reads like you are removing the wiring harness and coupler from the Bosch control module, you can instead remove the entire control module from the plastic tool tray. Remove the painted plastic trim from the Right side of the bike, locate the rear brake reservoir and left of that is a single plastic 1" long pin that secures the control module in the plastic tray. The plastic pin is held firm by a rubber grommet, with pliers grab that plastic pin and pull it up and out. On the left side the control module harness is tucked inside the frame tube, pull the control module harness away from the frame. The control module is now free, you can pull it out the Left side of the tool tray the harness coupler remains attached, no need to disconnect the coupler from the control module. Now the plastic tool tray is free to lift out the top, the battery follows.  I find this easiest, hope that is helpful.
Les 

[Shel]

Shel:   It reads like you are removing the wiring harness and coupler from the Bosch control module, you can instead remove the entire control module from the plastic tool tray. Remove the painted plastic trim from the Right side of the bike, locate the rear brake reservoir and left of that is a single plastic 1" long pin that secures the control module in the plastic tray. The plastic pin is held firm by a rubber grommet, with pliers grab that plastic pin and pull it up and out. On the left side the control module harness is tucked inside the frame tube, pull the control module harness away from the frame. The control module is now free, you can pull it out the Left side of the tool tray the harness coupler remains attached, no need to disconnect the coupler from the control module. Now the plastic tool tray is free to lift out the top, the battery follows.  I find this easiest, hope that is helpful.
Les 

Thanks for that Les.  But there just doesn't seem to be enough length to the wiring harness attached to the fuel injection control unit plug to allow the unit to slide out through the left side of the tray without disconnecting the plug.  And the control unit, plug & wiring harness are all squeezed into such a small space around the frame, I think it'd be impossible to bend and pull the harness out while pushing the control module out through the left side of the tray. 

In the end it was easy to pull the plug out of the module once I understood how to lever the screwdriver in a way that released the latch.  It's impossible to see what the mechanism looks like, as it's all out of site before getting it all apart.  From there, pulling the rest out and removing the battery was pretty easy.  But when I get a new battery and re-assemble everything I'll check to see whether or not what you're suggesting might actually work.

[Shel]

Shel:   It reads like you are removing the wiring harness and coupler from the Bosch control module, you can instead remove the entire control module from the plastic tool tray. Remove the painted plastic trim from the Right side of the bike, locate the rear brake reservoir and left of that is a single plastic 1" long pin that secures the control module in the plastic tray. The plastic pin is held firm by a rubber grommet, with pliers grab that plastic pin and pull it up and out. On the left side the control module harness is tucked inside the frame tube, pull the control module harness away from the frame. The control module is now free, you can pull it out the Left side of the tool tray the harness coupler remains attached, no need to disconnect the coupler from the control module. Now the plastic tool tray is free to lift out the top, the battery follows.  I find this easiest, hope that is helpful.
Les 

I just got feedback from a K bike pro who confirmed the method you outlined Les.  I thought I had tried that a the last time I pulled the battery a number of year ago.  But I guess not.   I really thought the wiring harness was too short to allow the injection module to slide out with it still connected.  Again... I'll confirm this when I put the battery back in.

[lmiklosy]

The harness is long enough, likely you have a cable tie strapping it to the frame making it appear too short. Remove one or two ties and this approach will work.  -Les

[Shel]

The harness is long enough, likely you have a cable tie strapping it to the frame making it appear too short. Remove one or two ties and this approach will work.  -Les

Ah yes... Thanks again for the tips Les  :2thumbup:

[daveson]

if u remove the cover to the control unit you can remove it and the box its in without disconnecting the plug
if you progressively lift the rear left tray as you progressively rotate the tray clockwise
on some bikes the lead may snag, keep an eye on it
on some bikes the battery is higher than original making it harder
after a few practice runs it gets real easy