Spark plug symptoms?

Working on my friends KZ1000 ´77. Bike has the condenser and stock coils.
Carbs cleaned and everything seems to be in good order.

The symptoms are that it’s only runs on 3.
No: 2 do not come in except lift off the spark cap a little from the spark plugs and then she comes in on no:2.
Any idea..?

Hawk1

I'd say first replace the sparkplug caps(they unscrew from the sparkplug wires), then do a compression check followed by checking the valve clearances.

If the valves have not been checked,there's a chance one or more may be partially open letting compression out of the cylinder(s).

Good compression might be between 135-160 PSI on this old engine. Hopefully the pressure is not too unbalanced on all four cylinders.

MFolks wrote:

I'd say first replace the sparkplug caps(they unscrew from the sparkplug wires), ............quote]

And maybe run a cloth around the white ceramic on the spark plug. Dirt or moisture may be causing a short.

Thanks for the info and help..
I will take a better look at these
things.

Hawk1

i was running on 3 out of 4 (#4 wasnt firing)... i took the plug out of its housing and grounded it... it sparked... but wasn't firing in its spot.... switched 3 and 4 plugs and magically #4 worked and #3 didn't.... all i had to do was get a new plug!!.... like i said though... i took the plug out... grounded it on the bike to make the circuit... and it DID spark... but it wasn't sparking inside the engine for some reason.... put one of my old plugs in from when i changed them out a few months ago... and voila!!!! full power again.... running on 3 out of 4 BLOWS!!!!... bout fell off my bike when i put that plug in to give me all 4!!!!