hello everyone. i have just purchased a 78 cb400 hawk. ive been through the carb cleaning every part. it still leaks from the overflow on the petcock side. gaskets are in good shape. the little rubber plug in between the jets fit loosely i was kinda thinking that could be the problem, if gas gets by those it would have more room to fill. any suggestions will be much appreciated.
thanks

The float could need adjusting (to lower the level of fuel in the bowls), or the float-needle and/or seats needs to be replaced.

the leak turned out to be as simple as a float bowl screw o-ring. i was wondering what the best way to go about adjusting the floats are. i can never seem to get it right with a ruler. the book says something about a special tool but i doubt i can get a hold of it.

See if this thread helps:
viewtopic.php?f=1&t=1593

The tool can be made out of a simple piece of cardboard-heck that's what it's made of. It's U shaped the space between the legs of the U is wide enough to clear the with of the float The tip of the legs to the inside base of the U is the depth your setting the float to. Put the tips of the U on the carb flang set the float so it just touches the inside base.

so ive gotten the carbs adjusted enough to run. i used the cardboard piece with the measurements as i was told. i think i may need a little more adjustment. when driving the acceleration is weak but as soon as it gets past that it takes off. does my fuel level need to be higher or lower? i appreciate all the help. one day itll be ready for the road.

#1 Do you have stock mufflers and stock intake? #2 If your at 3,000 rpms under redline in 3rd or 4th and hit it what happens?

i have aftermarket mufflers the intake is stock. the pre-chamber is pretty rusty. when i first got it to run it blew pieces of rust out of the mufflers but it doesn't do it anymore. when im 3000 under redline it continues to accelerate with no problems. struggles at the beginning of 1st and 2nd. when the bike hasnt warmed up it seems to do alright but as soon as its warm it begins.

The low rpm range is a sensitive zone as the motor is made to work best at the uper end of the range. That the bike does better cold than hot then there is an issue and most likely an over rich situation.
Next when your in second gear at the first gear shift point---that is bring it up to peak power in first --shift--and hit it-what happens? Peak power is about 500 rpms below the over run rpms (the orange zone on your tach)

sorry took so long to respond. i had to order a master cylinder before i started trying to drive it more. when i run 1st gear to the shift point and hit it in second it bogs down real hard. if i give it just a little more throttle it'll pick up and run as it should.

So you have lots of RPMs when you start out in second but bog down if you give it too much throttle??? Works okay if you give it just a little--is that what your saying?

It bogs down until it gets to the higher end of the gear after I shift to second it does the exact same thing. Almost like something is getting clogged. I don't have to open the trottle all the way I just give it a little more to get past the bog down. Once its past that it takes off no problem until I shift into another gear.

From all that I can gather from here your most likely running rich at partial throttle. Your problem may be part of what happens with the aftermarket exhaust but I'm not sure. If you own a manual it will give how to tune the carb--a smaller main jet is not it as your at patial throttle-moving the fuel needle setting tends to work from 1/4 and 3/4 throttle so it may help to change it's setting-the lowest range is controlled by the air/fuel idle setting but what options you have/need to try will be particular to just were in the throttle range your at-what your particular carb uses in the range your problem is in and- if it is due to your custom exhaust can an adjustment clear up all of your issue. I would try setting the fuel needle clip to the top position and see if that helps but check your manual and were in your throttle range this happens. When you change these bikes intake or exhaust these things may happen and sometimes all the carb fiddeling will not get things to work right. Let's hope your's is one that will tune to an acceptable running condition.