Topic: Go Dwn on clips on Needle or bigger Jet

[76supersport750F]

Hello I have a 76 750F  Rebuilt carbs and the engine pulls and has power up to 5K.

After that when I hit the throttle it lacks acceleration, breaks down, little popping. 

I drive it between 4 and 5K and short shift and it works great.  Not very good for the highway passing or getting out of the way quick.

I have the needles to Middle position and the Jet is 120.

Will going down 1 or 2 clips on needle cure this? How and What difference does adjusting
these needle actually make.

Is it best to just put in a 125 jet keeping the clip in mid position and will this cure my lean situation.  The plugs looked white on the tips.

Can someone from experience same me the time of taking the carbs off and on two or three times.   

Thanks and bye for now.

[mmtsquid]

I can't speak for your bike, but I would recommend ignoring the needle position for the moment and getting the plugs tan at WOT.
Once you have that, then start worrking your way backward (needle position, air/fuel screw, possibly pilot jet).

[HondaMan]

Your symptoms sound more like a vacuum leak than a carb jetting issue. Try improved hose clamps on the carbs and at the head: the jetting you have should be about right for the "F", if not a little on the rich side already. You may need new hoses. 

[david 750f]

Stock main jets on a 750F are 105's. Did you do any engine/exhaust modifications? I agree with Hondaman, check for vacuum leaks. Is your fuel petcock flowing properly?