Two Cylinders down

Hi All 
Ive got a strange problem cylinders 5  & 6 wont spark or they get an intermitant spark 

ive got new coils,caps  and cylinders 1,2,3,4 all run and get hot 

I just cant work out whats wrong

Thanks in advanced 

Pete

What year bike are you working on?

Let's talk this through. using one coil, say #1 - #6 coil.
In a wasted spark system such as the KZ1300, the spark travels down one lead, say #1 and jumps the spark plug gap (#1) to ground, then across the cylinder head to the other associated spark plug (#6) and jumps that gap then back up to the coil  to complete the circuit.
You noted that #1, #2, #3, #4 are all getting hot so that tells me the circuit is completing for coil #1 - #6 and  coil #2 - #5 and yet #5 and #6 are dead. so only two things could be happening here in my mind.
1.) spark plugs #5 and #6 are internally shorted allowing the spark to complete their circuits  or,
2.) You have a problem with the #5 - #6 carb with a "no fuel" issue

Electriciy will take the path of least resistance and if a "short" possibility is available then the spark will travel that path. Hence why it's called a short (path) to travel.

So maybe swap out 2 good plugs from 1,2,3,or4 with 5,6 and see what happens or
Take a spray bottle with gas and shoot some gas down #5, #6 carb throats and see if something happens.

 

its a 1980

I dont think its a fuel issue that may come later
Ive taken the cap off no6 just in case the cap was bad then turned the bike over to see if i get a spark but nothing

what i have notice is that when i turn the ignition on with the plug out i get a spark but then turning over nothing
the only other things i can think of is the pickups or the igniter

mr.p.wilkinson@gmail.com wrote:

I dont think its a fuel issue that may come later
Ive taken the cap off no6 just in case the cap was bad then turned the bike over to see if i get a spark but nothing

what i have notice is that when i turn the ignition on with the plug out i get a spark but then turning over nothing
the only other things i can think of is the pickups or the igniter

If the pick up or the igniter was faulty, then spark plugs #1 and #2 would also be a problem but you report that those 2 cylinders are firing fine. So I have to go back to grounded (shorted) spark plugs on #5 and #6