Switching wires

I want to check a problem on my 1980 KZ 1000.Cyl #3 doesnt seem to be firing correctly.When the bike warms up the header pipe is not as hot as the others,I spray water on them and #3 doesnt sizzle and vaporize instantly,it dries quick but not instantly.So what I want to do is switch the plug wires from #2&#3 and see if the problem moves to #2,which would tell me the problem is not the carbs.Is it safe to switch the wires as i describe,do 2&3 fire at the same time?

Yes. The bike uses the "wasted spark" ignition method, so plugs #2 and #3 both fire at the same time. Swapping the wires between them should provide a decent test of the coil and spark plug wires and caps. Ed

When was the last time the valves were adjusted?
Steve

Adjusted the valves a couple weeks ago.I suspect a carb problem,but I want to rule out the coils before I pull the carbs. When I first noticed the problem,I rode the bike about 25 miles and checked the plugs,the #3 plug was clean and dry,not sooty or wet.

If a brand new spark plug in #3 temporarily enables combustion, perhaps for a mile or so of riding, would assure the fuel level in #3 carb is within spec, using the clear tube method.

A too high fuel level in an otherwise perfect carb results in an over-rich mixture which might combust okay for a short time with a brand new plug until fouling out the new plug.

Good Fortune!

As above, particularly swapping the plug leads and checking float level. Best to just replace HT leads with new 7mm silicon and a set of non resistor caps, and maybe check your carb balance.

I ordered a fuel level gauge from Z1 Ent. Cant do anything til I get back on monday.I had the carbs rebuilt recently and it was running fine until I had to pull the carbs to get the starter out.When I put it all back together,this problem arose.I suspect maybe the float valve is stuck and I'm getting no gas or not enough to #3 since the plug looked normal after about 25 miles of riding with this problem.I assume it is firing some,since the pipe gets hot,but not as hot as the others.

stokes wrote: . . . getting no gas or not enough to #3 since the plug looked normal after about 25 miles of riding with this problem.I assume it is firing some,since the pipe gets hot,but not as hot as the others.

Yes, the normal looking plug indicates something other than a too rich mixture.

Possibly insufficient amount of mixture being received from carb #3 (such as imperfect pilot circuit);

And/or insufficient spark for whatever reason on plug #3.

If applicable, old hard cracked voltage-leaking worn-out plug wires should be replaced.

I prefer the longer-lasting solid core plug wires (as used in stock) over the resistance type plug wires. But it's just a personal preference, as the resistor style spark plug wires are expected to perform equally well provided they are accompanied with non-resistor caps and aren't accompanied with "R" spark plugs.

Good Fortune!

Couldnt switch the wires to 2 & 3 they wouldnt reach.Heres something new concerning the #3 cyl.When the choke is on and the bike is warming up #3 is as hot as the rest but when I turn the choke off and let it idle it cools down,leading me to think its a carb problem,not coil related.I check the bowl level and it was okay,a bit high even.I was concerned it wasnt high enough,so its not that.Rode it about 20 miles with new plugs and they all look fine.Any thoughts?

Pilot circuit clogged.
Steve

Here's one way to clean the pilot circuit.




Good Fortune!

I know the air screw has to be "set" when replacing,i.e. 1 1/2 turns,but what about the pilot jet? Does it just screw back in fully or what?