Front gear issues with middle ring (not always making it over) I've been trying to straighten out some shifting issues on a kid's bike, it's a Diamondback and is a few years old. On the front gear-set it has a few issues that I am having trouble fixing through l and h screw adjustment and indexing.


When shifting from the small ring to the middle it doesn't always make the shift, I have to twist it a little past the audible click to ensure a shift.
Also it's shifting into the big ring way too early. When moving the shifter about halfway to the audible click it's already moved over, letting go at this point results in a downshift.


From what I'm interpreting fixing one of these issues would make the other worse. Does anyone have some tips?
On the shifter handle, get the adjustment nut all the way in(where cable connects to the handle). Now get yourself some new brake outer and inner cable. Lube it very well, with oil(not grease, nor WD-40)

Now for derailleur, one screw is for the lower limit, the other one is for the upper limit. This is to ensure that the chain will not go out of the gears

Now shift into the lower gear, and fix the cable on the derailleur as tight as you can but without moving the derailleur. Once this is done you just need to use the adjustment nuts on the handle or the derailleur. I like adjusting it from the derailleur as the first fine tunning and any other from the handle, so I can keep track of how much wear the cables have.

Also check out if the derailleur is straight and parallel to the chain rings.  If it's not, it will not shift properly.