On a 2012 model: What kind of tools or special tools are needed to remove old bearings and install new All Balls in triple tree?
And what is Nut torque for head?
Though pulling the bearings into the head tube and pressing the bearing onto the tree spindle is the best way, you can do a good job using drifts, a tube, block of wood and a hammer. The drift needs to be plenty long enough to go through the headstock so you are swinging the hammer at least a reasonable distance from the bike frame - it's just easier that way. It need be nothing more than a piece of flat steel bar narrow enough to fit into the recess above the bearing and wide enough to have the required stiffness to take the hammer blows. You have to use it from above (easy enough) and below (a little more awkward). The end of the drift needs to be cleanly cut so that it doesn't slip off the bearing and you may need to reface the end if your bearings are particularly tight. There are two recesses and you should tap through each one alternatively so as not to coggle the bearing too much because this will risk damaging the bearing seat.
Presuming you don't have a long puller, the bearing on the stem is best removed by destroying it. I grind through it on both sides then finally split it using a cold chisel at an angle to the race. Clean up all grinding dust and don't grind anywhere near your work bench to prevent general contamination by metal and grind wheel dust. I wash the parts in hot water using dish washing detergent and immediately dry them, they'll be hot and they dry quickly.
The shaft bearing can be fitted using a suitable diameter and length of tube, push it on if you have a press or hammer it on, using a block of wood below the bottom yolk to prevent damage to the yolk. Again, as with the drift, the end of the tube needs to be square to the axis of the tube and finished so that there is even pressure to the bearing. Put a bit of rag over the bearing to prevent contamination while hammering it on. Don't forget to install the grease seal first!!
Fitting the outer races into the head stock is a little trickier. Partly because you are fitting hardened steel into soft aluminium, partly because they are a tight fit and starting them squarely is not so easy and partly because access to the lower one is limited while you are working from below. Anyway, without a puller, you have to drift them in with whatever tools you have to hand. This is where the block of hardwood comes in handy and I can normally find a socket from my socket set which is a suitable diameter to use as a drift. Again cleanliness is important and you need to keep your hammer and drifts clean too or they will shed their dirt on every hammer blow!
Always, always, lubricate the bearing fitting surface and its housing or shaft before fitting - did I say always!? And be scrupulously clean about everything - although they vary, as a guide, a human hair is about 4 thou thick so even a tiny piece of hair under the bearing will give it a coggle at the final fitting.
One thing to note; it's always better to use a large hammer gently than to use a small hammer wildly!
Now the tightening torque - I've buggered about with this numerous times and at present I've got it the best I can at 7lbs/ft and tightened the lock nut firmly. Tightening the locknut adds a little more preload, about the equivalent of 2lbs/ft more torque I reckon.
Now, the contentious bit - I have the taper roller bearings fitted because they came with a Traxxion tree and top yolk, I didn't have any deceleration wobble - No way would I fit them again and when there is the next rebuild of the front end, they will be relegated to the trash can and original Honda bearings will go back in.
Did I say no way?
However, I will admit to being at a loss to understand how the ball bearings are any different to the taper bearings once the preloads are set correctly - but they are.
I hope this is helpful info for you. Good luck with it.