After having this on going battle with my k100lt 1986 i've still got this bloody misfire. 

What i've done so far

Changed fuel pump
fuel filter 
fuel lines (even in the tank)
new full loom
different injectors
fuel rail
f.i brain
ecu
switch gear
plugs
leads
coils
temp sensor
battery
+ & - battery leads
exhaust
brand new inlet rubbers (£££)
air flow 
air box




head has been pulled and checked (fine)

it seems to rev clean when in (N)
but up the road when under load it's "bucking" and mis firing

Help me!

fuel level sender connector
ignition switch

I've changed the ignition switch twice.
Changed the fuel sender


It's mis firing on all four pipes

might be time to pull the afm
take the lid off it and check-test the anvil to pin connection of the wiper plate
there are documented fixes for this issue ...


heres what I found
umfortunatly most of my pics have disappeared from servimg



https://www.k100-forum.com/t1833p550-85-rt-resto-my-attempt-hey-im-not-into-making-a-show-bike#71318

Check that the 4 pin connector on the sender is actually connecting properly. The female part of the plug opens up a bit and can cause intermittent connection.
The mistake many people make is to check for continuity of the wires from each side of the plug and not the actual connection of the plug itself.
They only need to open up 0.1mm and you have problems. I ended up replacing mine with a 4 pin spade terminal connector from an auto shop and no more problems.

good point rick

some folks head directly for the major item  before testing the interconnects ....and proving them reliable  before continuing ....gosh we see this all the time

Making sure all plugs are properly seated might help as well., Often people have issues and then find out the computer plug was not properly seated. This is of course assuming that all connectors are clean ?? :-)

Make sure your spark plug leads are on securely. They shouldn't wiggle at all.

As Duck says, and make sure you have the bobbins on your spark plugs.

Hi there, misfiring is usually related to timing, I would check static advance, advance over the rpm range, hall sensors and connectors.
Best regards
JAP