cv 34 question

I have an 82 kz750E. Finally got her back together and got it to run. My starter needs to be rebuilt but my question is about the carbs. I have the kehin (sorry if thats spelled wrong) CV34's on it. I adjusted the floats and they all seem to be as close as possible without having the vaccum tester tool. When it starts it runs awesome, but I think it is getting too much fuel. is there a way to adjust the amount of fuel that gets pumped into the engine? Sorry if this sounds dumb but I dont know much about carbs. I know the jets are the stock sizes. Could it be getting too much fuel because I was starting it with the air box off? It ran great with it off, just idled high. I am going to put it back on but just got tired of taking it off and on while getting the carbs right. I appreciate any advice. What is a good place to start with the air adjustment screws on top of the carbs.

People with far more knowledge than me will come along but I'll mention a few things I have found out working on my CV34s.

-Float level is a different setting from what you adjust with the vacuum gauges. The float level adjusts how much fuel is in the bowl. The vacuum gauges are used to finely adjust and synchronize the throttle plates to one another. The float level is set by bending the little metal tine that the float needle hangs from and is checked using the clear tube method (use the search function on the forum to find it).

-What is it doing that makes you think its getting too much fuel? Popping sounds from the exhaust? Or just from the high idle?

-Are you running stock exhaust? Jetting may need to be changed if not.

-All sorts of funny things can happen with the airbox off. Someone else will have to comment on if it would make the mixture too rich. My initially guess would be that should make it too lean?

-There are two things you can try. First, underneath the carbs, between the middle two, there is a knurled screw that you can screw/unscrew to change how open the throttle plates are. This will affect your idle speed.

-The other thing, which you mentioned, is adjusting the idle mixture (a.k.a. pilot mixture) screws. If you look down at the top of the carbs, you'll see a single brass screw on each carb body. These adjust the air/fuel ratio at idle. Turning the screw IN (clockwise looking at the screw) will reduce the amount of fuel (mixture is more lean). Turning the screw OUT (counter-clockwise looking at the screw) will increase the amount of fuel (mixture is more rich). If you try this, you want to turn yours in.

-The factory spec for the screws is stated as "Two turns out from lightly seated"

-As far as running without the airbox, I have seen some people suggest cutting a piece of cardboard or hard plastic and placing it over the air intakes of the carbs to simulate the resistance the airbox induces. Someone else will have to describe that in more detail to you though.

I would expect with no airbox you are running lean. I am guessing this high idle is because of that. If all of your floats are adjusted to spec and you have your throttle butterfly's all adjusted to the same position (see "bench synch") and your airbox is on and you have no vaccuum leaks (plus carbs are clean), and the pilot mixture screws are set at 2 turns out, you'll have better results. You can always tweak these screws while it's running to find the sweet spot and do a vaccuum synch.

I'd also make sure your electrical systems are up to snuff and that you check your valve clearances.

Do yourself a big favor... get the Service Manual and read it front to back.

It can save you seasons of headaches and torture, and $$$.

If you have not changed the carburetor jetting, and you have the origional air filter/air box, carbs, exhaust, then basically everything just needs to be air tight, and set to defaults and the bike should run great.

thanks guys. I do have the factory manual, thats how I have gotten this far. Let me clearify my question. it seems like the number 2 carb is pumping out too much fuel. I think maybe I dont have the float in that one adjusted right cause thats all I can think of that would make it do that. I am not running stock exhaust on it. I made a set of 2 into ones for it. so Im sure I will have to re jet it at some point. I think I have the mixture screws out too far also. thank you for all your help.

it seems like the number 2 carb is pumping out too much fuel. I think maybe I dont have the float in that one adjusted right

Excuse my dumb question but do you mean the # 2 carb is leaking out the nipple on the bottom of the float bowl ?

....or that your spark plug is black from to much fuel ?

Either could be caused by to high a fuel level in the bowl and this can be checked using the clear tube method - do a search for clear tube method and you will find lots of posts.

A leak out the bottom of the float bowl could also be caused by bad float needle valve or dirt or cracked overflow tube.

it does leak out of the overflow nipple on the bottom of the bowl. When I block it off with a tube it then wants to come out through the carb itself. a small puddle forms in the carb. I think it is just adjusted too high. I will try and adjust and see what happens. thanks

Either adjusted too high or the needle is not seating because it is worn and/or dirty. I literally must have cleaned the lines from the gas tank to the float needles 10 times before I got all the crap out.

kzbobber1 wrote:

it does leak out of the overflow nipple on the bottom of the bowl. When I block it off with a tube it then wants to come out through the carb itself. a small puddle forms in the carb. I think it is just adjusted too high. I will try and adjust and see what happens. thanks

Or that carb has a worn and or dirty fuel inlet needle/seat assembly. In most cases when you have a high idle that can't be adjuster down, that an air leak or a very lean pilot/air screw circut. Like others commented, I am also very surprised that engine even starts and runs with stock jetting and no airbox.