Starting a rusty '82 KZ750

I know this seems too obvious, but iit's happened in the past so...
is there any chance the plug wires are on the wrong plugs? The right coil normally fires 1 and 4. The left coil normally fires 2 and 3. At least that is how it came from the factory. It's possible to change the physical locations of the coils, so it could be opposite.

Like I mentioned earlier, you have to remove the pilots, bleed pipes, pilot screws (and spring, washer, and O-ring) and clean all the parts and passages. Light must pass through the pilots and bleed pipes or the bike won't run right if at all. You can NOT clean these parts and passages by shooting stuff through the carbs.

Nessism wrote: Like I mentioned earlier, you have to remove the pilots, bleed pipes, pilot screws (and spring, washer, and O-ring) and clean all the parts and passages. Light must pass through the pilots and bleed pipes or the bike won't run right if at all. You can NOT clean these parts and passages by shooting stuff through the carbs.

Right. I did follow your suggestion before and did pull it all apart clean and inspect all passages. I'm perplexed. Checked float fuel levels and 3 and 4 were lower than 1 & 2 so I adjusted the float tangs on them which appeared to improve fuel level and delivery. 3 seems to fire more regularly and 4 header is warmer to the touch so I think that helped. But 4 is still cooler than all the rest. I attempted to synch carbs and hope it would solve some of the issue. Balanced 1&2. Then 3&4 then 1,2 & 3,4. The result is not great. Need to do it again but it is an improvement because before I couldn't even keep all the bottles filled. #1 way to much vacuum.

82 Kz750 initial carb synch

Have you considered buying a set of gauges to balance the carbs rather than using bottles of water? Ed

650ed wrote: Have you considered buying a set of gauges to balance the carbs rather than using bottles of water? Ed

Yeah. I'm over budget. Kids, mortgage, blah blah blah

Pulled carbs again. Broke them down again. Pulled all brass and sprayed all circuits to ensure clear of debris again. Reinstalled. 1 & 2 firing, 3 firing intermittent, 4 no fire. Fuel level test results below (1 , 2, 3, 4). My adjustments to the tangs on the floats clearly did not work. Help.

With the fuel level so low that means the float is set too high. Did you bend the float tang down by mistake? Another option is that the float seat bore so to speak is rough and the needle isn't moving smoothly up and down in it. A piece of rolled up gray scotchbrite pad smashed down into the seat with a small screwdriver will polish up the seat. Also, when you removed the bleed pipes and pilot jets did you hold them up to a light to make sure the orifice is open? It's critical that you visually verify that the tiny hole allows light to pass through. Lastly, did you verify spark on #4?

Thanks again,

1. Tangs are set considerably lower in 3 & 4 than in 1 and 2. If the carbs are right side up, I pushed the tangs down). The floats on 3 and 4 are topping out before they even fully depress the little springy nub at the bottom of the needle. (pictured below)

2. Will clean the float seat bores next
3. all jets and pipes are absolutely clear of debris. meticulously examined every single little hole
4. #4 has spark (brand new plugs as well)

Just to get a starting point for the float high:




Position the carb Body to an angle so the float tang barly contacting the needle valve pin and do your measurment.

Scirocco wrote: Just to get a starting point for the float high:

Position the carb Body to an angle so the float tang barly contacting the needle valve pin and do your measurment.

Wrong carbs. OP has CV34 Keihin's. That info is for Mikuni's.

Thanks Nessim for the info, just miss he has Keihin carbs.

yeah, yep. thanks Scirocco. Problem is I did the float height check my manual called for the first time I reassembled them. Since then I only recently monkeyed with the tang. This is why I'm so perplexed. And also, regardless of fuel height wouldn't the cylinder be firing anyhow even with a lean mixture? It has compression (129), it has fire, evidently is does not have fuel and I'm lost at this point. I'm a pro at pulling the carbs and breaking them down. I just suck at making them work.