Tumbleweeds 1977 KZ650 Rebuild/Reform (Pic Heavy)

If it was just pods and jetting, all four plugs wouldn't look so different.

As you open a throttle, the mixture gets richer. The faster you open it, the more rich it will be. So the symptom sounds like a rich condition. Plugs 1 and 4 look super rich and wet. Is it gas or oil?

I would also swap some ignition stuff around. Because it's 1 and 4, there may be an ignition issue for those two cylinders. They share ignition parts... coils and points.

How long do these engines usually take to warm up at idle?

At about 1300 rpm mine warms up enough to turn the choke all the way off and ride in about a minute or two depending on the outside air temperature. With the choke all the way off it idles at around 1000 rpm. Ed

Okay update to the bogging issue. I have my pilot screws (under the carb, engine side) turned 4 turns out, and it reduces the bog. I understand that is more than double where they should be.

I am having a hard time finding out what circuit that pilot screw affects. Do I need to go bigger on the pilot again?

EDIT: 5 turns out and the condition is still getting better, almost gone.

How about cleaning your carbs. Sounds like your idle circuit is partially blocked.


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Ok so here is the story guys, and I feel a bit dumb. As it turns out I just wasn't letting it warm up enough. I let it idle for a few minutes, and took it around the block about 10 times instead of the usual 2. On the last pass around it felt like a different machine. I set the pilot screws back at 1.5 turns out. As it is, I am pretty happy with the way it runs and will focus now on finishing the seat and brake/signals. Then it's time to paint.

I am about 95% sure I am going to do Kawasaki green.

Plugs are looking much better, but I still need to buy a fresh set so I can better see what the cylinders are doing.

I'm still only on a bench sync so I need to invest in some vac gauges as well.

Procrastinating the seat, and slowly trying to find/make my parts.

When you look into sync gauges if you see some like the ones below I can vouch for them being excellent. Before I got these I had a set of cheapies, and one of them quickly became very inaccurate. Ed