If it only runs for a few seconds then my guess would be the FIM is not seeing the 700+ RPM signal and dropping the ground to the fuel pump relay or starter is dirty not providing the ground path. Did it run before the cafe mod?

Try keeping the start buttom pressed down and see if it keeps going.

Caveman - bike ran well after the mod. I had the tank off to the side while changing the coolant. Running well while burping the radiator and it just died out. I’ll look into the ground issues and may take off the starter and give it clean.

Rick G - no change in keeping the start button held down. Just cranks.

The EFI relay doesn't earth through the starter

My bad, should have checked the schematic before opening my big mouth.

Hey, afeiest.
    Surfing the internet, looking for parts for an 88 K75 I have, I came across you add last night. Might have been craigslist - don't remember. If you have all the stock parts that came off when ya did the kit, Id be very interested in buying the bike separate. 
    I've had my 88 apart long enough, that the tank grew legs and walked off. The whole bike is rough, but it will be hard for me to ride it without the tank! Some tools and lawn equipment went along with it... guess someone thought they deserved it more than me
    Anyway, let me know what ya have with it.
DJP

DJP, 

If you are looking for a 75 tank then the 75RT tank will not fit.  The 75RT actually uses the K100 tank and not the 75 tank.  The 75RT uses a modified K100 frame and hence the difference.  It also uses the K100 side panels either side of the battery.  

Dave.

Dan Pete,

TacKler is right on about the tank.  As for the parts I took off the bike, many I already sold or gave away to other's on the forum.  If you have a donor bike already, with a little time, you'd likely get my '92 running.  Nevertheless, for understanding what was removed from the stock bike, here is a pic.

-Aaron

Thanks... seeing current pictures of the bike, it’s a lot of stuff taken off. Cool pictures of it all laid out.
The K75 and K100 tanks are shaped different, and some minor mounting differences from different years as well. But the differences are minor. The frames are the same, except for the angle of the tubes from the steering neck to the top engine mount location, since the 3 cyl is shorter than the 4 cyl.
My goal for my non stock bike is for more of a RS, that sadly bmw never made! If I use only bmw parts, I would need an RT or a K100 tank... but the minor differences are actually easy to work around.
I’m a really long way from you, so don’t know if we could work anything out, but would be interested in a picture of what’s left, if ya get the chance
Or a heads up of a tank for sale, at a low price!
Thanks.
DJP

Bike with kit SOLD.  Thank you for your interest.