Brothers, I ask you're help, I recently (over the winter within 2 weeks) covered about 1000 miles around scotland, between all the shit, gritters, ice, snow etc she's performed pretty well, but in the last 100 miles problems came to light, first of

the throttle cable snapped (fixed the next day)
One spark plug lead had snapped and therefore running on 3 cylinders (temporarily repaired with an electricians chocolate box connector)
Broke the speedo drive with a disc-lock (got a replacement this morning and fitted, works fine)
ran out of fuel on the M8 and then the filler cap froze once I had obtained fuel, so I had to piss on it to melt the ice infront of nosy police and a guy watching on camera (just thought you may find that amusing)

Since the first lead snapped, I fear that there may be another rogue cylinder not firing, I cannot get above 10k revs (forcing it) and then when I let the clutch out, it just seems to kind of splutter and become less interested in funtioning. possibly also a clutch issue?

Your thoughts / Ideas will be appreciated.

F

Seems that just cylinders 1 and 2 aren't firing, checked spark and both are fine, carbs are functioning normally, possibly a compression issue? i ran it for a couple of minutes, both 1 and 2's exhausts were ice cold while 3 and 4 were roasting.

so does anyone think a compression test should be in order just to be safe?

could it be electrical related? timing related? i also swapped both spark plug leads twice so they are back to there original ports and it made no difference (just incase i put them on in the wrong order) and still no success.

anyone got more ideas for me to try?

could potentially looking to buy a new / used +working CDI for gk73a, anyone got one?

It cannot be the cdi as it feeds 2 coils- the nearside coil feeds cylinders 1 and 4, the other feeds 2/3. the fact that 3 and 4 run shows the cdi is ok. The fault with these cylinders has to be one of three things- fuel, electrical or compression so you need to figure out which it is before you buy anything.

i now need a coil, i thought it could have been the CDI but upon further inspection of the wiring diagram and further testing, seems its the left coil (for cylinders 1 and 4)

Are 100% with the coil, have you swapped the left and right over to see if the bike fires differently as you posted 1 and 2 not running and 1 and 2 use both coils + have you checked that you have 12V at the coil.

yea, i checked the coils and leads, ones reading 11.6 (normal) the other 7.2 (low) and swapped them both in testing, ones not going so i need a new coil. sourced one from a bandit 400 should be here by thursday (apparently)

problem solved! thanks for you're help!