1. Go around the wheel and use a tension gauge to make all the spokes equivalent in tension. Then go around and fix the lateral and radial runout.
2. Has to do with geometry and thickness of the tires.
To generalize the article even more, the way a bike turns is like this: for a given speed and radius through a corner, there is a necessary lean angle. That lean angle determines the camber thrust of the tires, which is the centripetal force that makes the bike turn. However, you also have to make the bike yaw, which means the front has to generate a greater sideways force than the rear. This is accomplished through adding steering angle to the front tire. The longer the bike is, the greater the difference that is needed between front and rear sideways forces.
Furthermore, the steering angle of the front tire is affected by the head angle (90-rake angle), and geometric trail (caster effect). The greater the geometric trail is, the more the tire wants to resist turning. The greater the speed, the higher this effect. Conversely, the slacker the head angle is (lower in value, greater rake angle), the more the front tire wants to turn into the turn (because the wheel axle lower in height with increasing steering angle).
The reason why you generally lean the mountain bikes under you are 2 fold. First, the bikes are longer, so naturally you need the greater difference, which means you need more force from the front. You would exceed the max slip angle of the front tire if you stayed upright, especially on looser dirt. So instead, you lean the bike more to engage camber thrust. Secondly, the tires on mountainbikes are designed with side knobs specifically for cornering, so you want to engage those knobs.
The opposite problem exists on street motorcycles, where the bikes need to be low enough to the ground to not backflip on acceleration, which limits the available bike lean angle. So instead, riders learn to hang off the bike. This in turn requires the front end to be turned more. As a consequence of this, bikes understeer or oversteer behavior is greatly depends on the front end geometry (rake and trail). The trail forces are magnified at the higher speeds, so you need careful tuning of things like fork offsets (which control trail), and rake angle, both of which are affected by suspension moving up and down.
Yet, on supermoto bikes (i.e dirtbikes with street tires, popular in europe), you don't have the ground clearance problem, so you can actually corner them either like street bikes with knee down, or dirt bike style while leaning the bike under you.
2. Has to do with geometry and thickness of the tires.
To generalize the article even more, the way a bike turns is like this: for a given speed and radius through a corner, there is a necessary lean angle. That lean angle determines the camber thrust of the tires, which is the centripetal force that makes the bike turn. However, you also have to make the bike yaw, which means the front has to generate a greater sideways force than the rear. This is accomplished through adding steering angle to the front tire. The longer the bike is, the greater the difference that is needed between front and rear sideways forces.
Furthermore, the steering angle of the front tire is affected by the head angle (90-rake angle), and geometric trail (caster effect). The greater the geometric trail is, the more the tire wants to resist turning. The greater the speed, the higher this effect. Conversely, the slacker the head angle is (lower in value, greater rake angle), the more the front tire wants to turn into the turn (because the wheel axle lower in height with increasing steering angle).
The reason why you generally lean the mountain bikes under you are 2 fold. First, the bikes are longer, so naturally you need the greater difference, which means you need more force from the front. You would exceed the max slip angle of the front tire if you stayed upright, especially on looser dirt. So instead, you lean the bike more to engage camber thrust. Secondly, the tires on mountainbikes are designed with side knobs specifically for cornering, so you want to engage those knobs.
The opposite problem exists on street motorcycles, where the bikes need to be low enough to the ground to not backflip on acceleration, which limits the available bike lean angle. So instead, riders learn to hang off the bike. This in turn requires the front end to be turned more. As a consequence of this, bikes understeer or oversteer behavior is greatly depends on the front end geometry (rake and trail). The trail forces are magnified at the higher speeds, so you need careful tuning of things like fork offsets (which control trail), and rake angle, both of which are affected by suspension moving up and down.
Yet, on supermoto bikes (i.e dirtbikes with street tires, popular in europe), you don't have the ground clearance problem, so you can actually corner them either like street bikes with knee down, or dirt bike style while leaning the bike under you.