Have spark, Have gas, Carburetors rebuilt, NO RUN!

Ok, I'm here for troubleshooting on why this KZ 650 won't run. It is a 1981 KZ 650 D4. First I'll start off from when we got the bike. When we bought the bike it hadn't been run for years so we get a new battery, put new gas in, and fix the starter switch and it started up with some starting fluid. It was rough, but it ran. Rode it up and down the street a few times.
My brother changed the oil and took the carbs apart, put them back together, put them on the bike and nothing couldn't even get the thing to fart. So I figure he did something wrong and rebuilt them myself, cleaned heavy deposits of grime out of every bowl, every jet, and the float needles, resync'd the valves on the Mikuni carbs, put them on myself and it still wouldnt run. Frankly I'm out of ideas as to why it won't run now. The only thing I think is weird is that when I'm turning the bike over and put my hand over the open end of any of the carbs I feel it suck my hand in then blow air back out of the carb.
I am new to working on motorcycles, so I need to know how much gas to give it, how much choke, and if there's anything else that I need to do to get it to start up. Thank you.

Just for shits and gigles have you checked the timing? I would also make sure all the tiny tiny passeges in the carbs are free from any obstructions, I use compreseed air for this. If the bike sat and you put gas in it you may have sucked up trash from the tank, and it will clog passeges that you can not see. That happened to me a while back. Also make sure the coil wires did not get hooked up backwards firing the wrong cylinders. Have you done a compression check yet?

I just cleaned the tank yesterday not to mention the pet cock has a filter and I've put an inline filter on it. Not sure how to set the timing but nothing there should have been touched since when it ran and the rebuild. I also cleaned every duct of the carburetors out with compressed air after sitting each component in chem dip for 30-45 mins so I'm absolutely sure it's not the carbs fault. We have not touched the coils at any time since we've had the bike, and all cylinders have compression.

i m gonna go out on a limb and say those carbs need cleaned again....i would put an inline filter in also...the fact you had it running once, but now it doesnt, leads me to think there is a bit of dislodged crap in those carbs...got any pics of the carbs? the part that you redid carbs and had to get rid of heavy deposits means clean em again...4 cans carb clean,a wire carb orrifice cleaning tool and some compressed air...and when you think they are clean, do em again.....make sure you have eye protection....good luck

keith1 wrote:

i m gonna go out on a limb and say those carbs need cleaned again....i would put an inline filter in also...the fact you had it running once, but now it doesnt, leads me to think there is a bit of dislodged crap in those carbs...got any pics of the carbs? the part that you redid carbs and had to get rid of heavy deposits means clean em again...4 cans carb clean,a wire carb orrifice cleaning tool and some compressed air...and when you think they are clean, do em again.....make sure you have eye protection....good luck

X2 It took me a couple of times on my 900 and four times on my 650. I can take the carbs apart blindfolded. Are the needle valves stuck how about float level. Dont take offense at redoing the carbs trhis is the nature of the beast.

Float needles move freely and the floats themselves are set at 23mm

Make sure to pull the pilots and clean them and the pilot passages thoroughly. that is what i had to do with my 1979 KZ650D when i got it. Like yours, my bike had been left in the corner for a couple of years before i got it. repeated soakings with lemon juice even failed to clean them properly, i finally took a small 1/8" diameter flat head screwdriver and removed the jets, then blew out the passages with compressed air. i cleaned the jets with a jet brush before replacing them and everything was good after that.

I have had old gas gum up small engines and hang the valves open. Did you check compression. At the very least use your finger over each spark plug hole and see if they feel about the same. Make sure all spark plugs are out when you do it. Out of time or an intake valve hanging open can blow back thru the carbs. Especially an intake valve hanging open when there is compression coming back thru carb. Good luck with it.

where are the pilots adjusted to?

Striker wrote:

Float needles move freely and the floats themselves are set at 23mm

The physical measurement setting of float levels is notoriously inaccurate. Should perform clear tube test to verify actual fuel level inside float bowls.

Here's a method for cleaning the pilot circuit.

Good Fortune!

[Click on image to enlarge view.]

Make sure to pull the pilots and clean them and the pilot passages thoroughly. that is what i had to do with my 1979 KZ650D when i got it. Like yours, my bike had been left in the corner for a couple of years before i got it. repeated soakings with lemon juice even failed to clean them properly, i finally took a small 1/8" diameter flat head screwdriver and removed the jets, then blew out the passages with compressed air. i cleaned the jets with a jet brush before replacing them and everything was good after that.

Patton wrote:

Striker wrote:

Float needles move freely and the floats themselves are set at 23mm

The physical measurement setting of float levels is notoriously inaccurate. Should perform clear tube test to verify actual fuel level inside float bowls.

Here's a method for cleaning the pilot circuit.

Good Fortune!

[Click on image to enlarge view.]

It's a good possibility that that #6 orifice if it was clogged is still clogged, even though I blew out every passage with compressed air I didn't stop to think how many of them are interconnected and didn't block any off with my fingers. I will pull the carbs tomorrow and repeat the process. What is the clear tube test?