Carb tuning all over the map.

Just bought a 1980 KZ440 from a friend with roughly 8000Km's on it. He said it was sluggish at the mid band and probably needed carbs cleaned. Noted the turns for the fuel/air mixture screws and cleaned the carbs entirely. After reassembling, having nothing but trouble. First scenario was starting with full choke and high revving. Closing choke only made it worse. After trying to adjust screws, had a situation where #1 was not firing at all. I've even cracked the throttle and heard the top of the carb hitting the top cap. I have no clue as to the problem. One minute both are running and revving out of control with no idle adjustment added on the center screw, to only one cylinder firing. Not sure what to do now. Any thoughts?

Hello and welcome to the KZR forum

A lot of KZ 400 /440 twin carbs are exchanged with newer 2-stroke engine carbs.
This leads to misinterpretation. Are you sure you have the right carbs on?
Take some pictures of your bike / carbs to get a better overview for us.
First you have to sync the carbs and check the intake boots for leaks.
Have you a service manual?



www.kzrider.com/modules/ServiceManuals/kz440.pdf

Michael

Hi, thanks for the prompt reply. Yes, I do have that very manual as well as the Clymer book. When I get a chance I'll get some photos up of the carbs. They match all the diagrams. I believe they are Keihin CV36's.

Thank You, Murray

Is the complete stock airbox installed with a stock air filter? On the 440s the airbox is often times removed or missing the cap, which cause running problems.

Valves adjusted?
Steve

What type of air filter are you running? If stock then I would look for air/vacuum leaks.

Running original airbox. Replaced the old dirty green filter foam with some new stuff. (Black)

Since you have it rigged, you need to make absolutely certain that it's sealed where the air filter housing cap meets the airbox body. If not, you'll have vacuum leaks. It needs to be a good fit & not move.

This is how the bike came. Looks like they had to pop riveted the flap.
I've seen guys tweek carbs without even having air filters on . I would think the critical seal is on the engine side? Is that not correct?

Just removed, (difficult) the carb boots to the engine and would like to replace. Any ideas as to whom to order from? Quality parts of course.