Carb Id

I started this post in engines, but realized this is a better place for it. I have a 81 kz750 it idles fine and runs hard past 5k. But right around 4500 it just falls on its face like its over fueling or something. Also after decelerating if i dont keep the RPM's up it doesnt want to take off right away, like it has a ton of extra fuel. Im not sure what the carbs are for all I know is that they are Mikuni, and are off a 1000cc bike or rejetted. Th guy I bought it from wasnt sure which one it was. Im just trying to figure out what they are so I can rejet them.

Heres some pics hopefully this helps.

sorry my pics arent working out

Only one pic is allowed in each post.

Try again by replying to your own post with the next pic.

Then repeat until you have all the separate pics showing one pic per post in successive posts.

Good Luck!

Your initial post had several of the same pic.

Do it again the same way but with only a single pic.

Then reply to your own post with a new post showing the next pic. And so on. Putting only one pic in each post.

Good Luck!

Sorry that took so long, wow i feel stupid

The air cut off valves mark this Mikuni BS34 assembly as 1983 or newer as the air cut off valves were first used on SOME assemblies in '83.

What size needles should I use. It currently has a stock airbox w/ a k&n, 4 into 1 and stock ignition.

What size needles? I am not sure what you are talking about. Stock jetting is probably #127.5 main jets and #37.5 pilot jets. I doubt the K&N drop in filter or 4 into 1 changes the flow enough to warrant serious rejetting but you will want to check current jetting and let me know what is in there. There should be metal plugs in the pilot wells as the pilot jets pick up gas via a cross passageway with the main jet well. You will need to pull a plug and unscrew the pilot to see what is on its side. The main jet has a number stamped on it... some cleaning might be necessary to read the number.