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1Back to top Go down   ['93 K75] L-Jetronic teardown Empty ['93 K75] L-Jetronic teardown Sun Mar 28, 2021 2:31 am

roach374

roach374
Silver member
Silver member
I had this idea to chop up a perfectly good motorcycle (1993 K75 standard) and turn it into a Cafe racer. I wanted to move the annoyingly huge Jetronic EFI under the seat, but it just won't fit. So rather than drop $1500 on some aftermarket thing, or figure out how to make a Megasquirt work with the K75's set of sensors, I wondered if I could "make it smaller". 

After all, it can't possibly be full of electronics in this gigantic thing, can it? There must be some dead space, or some optimizations I can make, put it in a smaller enclosure, something? As an automotive component, it's designed to be bulletproof, huge honking connectors, weatherproof, etc. Maybe there's some room for cuting corners in the name of space.

Anyways, if anyone else is curious what one of these things looks like on the inside, I got a couple of pictures along the way.

Two halves of the Jetronic, separated. On the metallic "shell" half, you can see the small metal clips around the edge, which I had to bend back in order to slide the metal shell off. I also had to destructively remove the anti-vibe rubber mounts (there might be a way to avoid destroying these, but I didn't need them).
['93 K75] L-Jetronic teardown Pxl_2011

There is also a small runner gasket between the two halves. 

['93 K75] L-Jetronic teardown Pxl_2012

First thing that was immediately obvious:

  • There is not, in fact, a lot of "dead air" inside this enclosure.
  • This is a 2-sided PCB, with mostly analog / passive components. Very '90s, and possibly hand-soldered.


The PCB is held in place in the plastic half of the enclosure by a couple of clips (visible on the bottom edge of the PCB in the above image), and a single screw (visible in the top-right of the PCB in the above image).


These '90s PCBs were crazy flexible, apparently

['93 K75] L-Jetronic teardown Pxl_2013



Last edited by roach374 on Sun Mar 28, 2021 2:38 am; edited 2 times in total


__________________________________________________
1993 K75 standard
    

2Back to top Go down   ['93 K75] L-Jetronic teardown Empty Re: ['93 K75] L-Jetronic teardown Sun Mar 28, 2021 2:36 am

roach374

roach374
Silver member
Silver member
Once I popped the PCB out of the retaining clips and removed the One Screw, it was easy to slide it out of the plastic enclosure

['93 K75] L-Jetronic teardown Pxl_2014


And here's the money shot. As you can see, there are a lot of de-populated components, so I suspect this PCB was used in other designs as well:

['93 K75] L-Jetronic teardown Pxl_2016


Anyway, it's pretty clear that I won't be able to get much space saving out of this thing. Fortunately I only need to shave off about half an inch, so I might remove that gigantic connector and replace it with some direct-to-board wiring or something.


__________________________________________________
1993 K75 standard
    

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