Carbs geting gas, but not to spark

1979 KZ750 Twin

Just put the bike back together but I can not get her started. The carbs are getting gas and on the kickstand side, the card vent line is leaking gas when the gas is on.
Any ideas why that would be?

Also I checked my plugs by taking each one out and placing it on the block to see if they spark and each one does. But I notice there is no smell of gas. They are not even wet. Any ideas what is stopping gas from reaching the plugs?

lroberts wrote: 1979 KZ750 Twin

Just put the bike back together but I can not get her started. The carbs are getting gas and on the kickstand side, the card vent line is leaking gas when the gas is on.
Any ideas why that would be?

That problem is so common it should have it's own sticky. It means the carb needle/seats have a problem sealing and/or the floats need to be adjusted to get the fuel levels in the bowl right.

If not already done:

rinse fuel tank with clean solvent or gas, clean petcock assy and install inline filters. Crud coming down will cause sealing problems.

Then drop the bowls and remove the floats/needles/seats and clean and polish them so they will seal.

use the clear tube to set fuel levels and no more problems.

Well just got done taking the carbs off and cleaning them. Took both all the way apart and even took the air compressor to them. Back on now and that seem to fix the gas leak from the vent but still not starting. Plugs still seem dry to me. Think I am going to run and grab some new plugs and see what that does.

Side not.... While I was trying this today the solenoid went bad so I am having t turn the key to on, set the switch to run, and then jumping the solenoid with a screw driver. The engine turns over great and I am getting spark on both sides but its not a great spark.

Any ideas?

When trying to start it do you have the choke on full and you are not touching the throttle? Ed

Well I have tried the following....
Choke not on.... Then try giving some gas
Choke on.... Then try giving some gas

I would think it would at least sputter or something. My plugs are REALLY black and even though they are sparking I am wondering if its the plugs.

Either that or......
I had to run a new wire from the points but I do get spark but it does seem weak.

Ok so now I have new plugs, confirmed they are sparking yet still no start. I am really at a loss. Carbs have been cleaned twice, new plugs, new battery.... And I have gas leaking again front the vent. Could the no start be electrical?

Also how do I adjust the float to stop the gas leaking from the vent?

lroberts wrote: Ok so now I have new plugs, confirmed they are sparking yet still no start. I am really at a loss. Carbs have been cleaned twice, new plugs, new battery.... And I have gas leaking again front the vent. Could the no start be electrical?

Also how do I adjust the float to stop the gas leaking from the vent?

Flooding = flooded engine which is impossible to start.

You need a factory service manual. I got one on CD for $5 on ebay.

lroberts wrote: Well I have tried the following....
Choke not on.... Then try giving some gas
Choke on.... Then try giving some gas

I would think it would at least sputter or something. My plugs are REALLY black and even though they are sparking I am wondering if its the plugs.

Either that or......
I had to run a new wire from the points but I do get spark but it does seem weak.

To start a cold KZ engine the drill is as follows:

Fully charged battery
Petcock "On" (or "Prime" if vacuum actuated)
Kill switch in "Run"
Choke On
Ignition key On
Do not touch the throttle at all.

With the above done pull in the clutch lever and hit the start button
OR
Don't pull in the clutch lever and use the kick starter (if your bike has one).

Ed

I can tell you this. I also have the 1979 750 twin. At various times in it's life it has flooded gas out the overflow for various reasons (mainly I was too busy to fix it) I learned from experience when ever I see the gas puddle, don't even bother cranking because it is NOT going to start. I'd turn off the petcock and spin the spark plugs out to let the gas evaporate.

If your carb is flooding, it isn't going to start.

Well got her started! So I took the carbs off for the 3rd time and used 2 cans carb cleaner on them. I put carb cleaner in every hole I could find. Took out the jets and places them right up to the straw on the carb can and blasted them. After all that I did about a 3 hour soak and then took the air compressor to everything. Put it all back together and she fired right up!

Still have gas that leaks out the kick stand side carb through the vent but that I can live with.