81 kawasaki KZ 750 help

[telefunkin]

I removed the carbs and cleaned them again, soaked the jets and blasted them out with compressed air.

The needles don't have clips, the top of them looks like a nail head. I couldn't find any way to adjust them.

Put everything back together and there's no change.

On my test run, I got up to full speed and slowly started letting off on the throttle to find out where it's starting to lose speed. Turns out it's at half throttle. Did it again in reverse and same thing, it's hitting 120kph at about half throttle and won't go any higher.

This is really starting to bug the hell out of me.

[telefunkin]

Update:

Pulled out the plugs again, and they're black. This means it's running rich right?

[thespirit]

Did you check float heights?

Yes, black means rich. Surprised you aren't hearing some backfiring or popping in the exhaust.

I would check your float heights now. It's possible that you are just draining the float bowls faster than it can fill them.

Do you have a fuel filter in place? If you do, make sure it's a pretty high flow filter. That can restrict the amount of fuel getting to your carbs too. Check for any kinks in the fuel line, etc.

I would look at float heights though. What size are all your jets and which clip is your needle set on?

[telefunkin]

Took the carbs off again and checked the floats. They were as high as they could be set. Actually touching the top of the float chamber. I wasn't sure how high these are generally set so I dropped them about 1/8th of an inch.

Then I cleaned everything out again.

There really wasn't any noticable change.

[thespirit]

What are they set to now?

[telefunkin]

Finally picked up a fuel level gauge yesterday. The floats are set correctly now.

This did not change anything. It still will not go past 120 and it's burning an insane amount of gas.

[thespirit]

Do you happen to know what size pilot and main jets are installed? Which carbs do you have?

[thespirit]

Also, have you done a compression check yet?

[telefunkin]

I forgot to write down the jet sizes and I haven't done a compression test.

The plugs are still going black, and it's backfiring when I down shift or rev it up high and then back off on the throttle.

[thespirit]

That all means that it's running rich. That will cause it to use an abnormal amount of fuel... The jets could be the wrong size or the choke plungers could not be seating all the way down or the air mixture or fuel mixture screws could be not set right. I would check the jet sizes first.