Ride Height
Bike geometry! Well this is a bit more complicated! Well, I'm just going to toss bits in willy nilly for this page. The geometry makes a huge difference but for the most part the manufacturers have done the work for you already. Most stock streetbike's geometry can only be changed by sliding the fork up and down in the triple clamps. Most good aftermarket shocks have ride height adjusters, these also change the bike's geometry.
Let's start with the fork. To move the fork up the triple clamp/lower the triple clamp on the fork, loosen the clip on and slide it down the fork tube the distance you want to change, then tighten. Then just loosen both triple clamps and let the forks slide until they stop on the clips ons. (many bikes come from the OEM with the clip ons bolted to the underside of the top triple.( Get rid of those bolts anyway, without them you may not have to replace your clip on if the bike lowsides or tips over) Do not make huge changes (2mm at a time is good) the forks rake/trail works kinda like a shopping cart castor, the closer the fork gets to 90 degrees, the less stability and resistance to tankslapping it will have. The further down the fork tube the triple clamp goes the closer the fork gets to 90* The benefits of a proper fork height are: quicker handling and a small amount of extra weight on the front tire which may make the front feel more planted.You can also make changes to how much the bike stands up while braking in a turn by reducing the trail and thereby getting a greater torque advantage.
The rake is the angle the blue line is from 90 (the blue line is to the steering head), the trail is the distance between the red and the blue line. This picture is simplistic and does not show any fork offset (where the fork is not inline with the steering head) if there is offset then the trail will change accordingly. This is one way to increase the rake and maintain stability.
Now the rear ride height: The rear can be raised/lowered best with the ride height adjuster found on most good aftermarket shocks or by shimming the shock. Another way (but not as good) is to use more or less sag. Beware though, raising the rear ride height will take some weight off the rear tire, thus taking some of the traction away and hopefully not overloading the front. With the rear you can also adjust the weight bias, fork angle,(as you can a bit with the front) and you can also adjust the squat characteristics:
" the placement of the swingarm pivot in relation to the line in the center of the output shaft and the center of the rear axle establishes a neutral, squat, or anti squat situation in the swing arm geometry. placing the swingarm pivot too high above the line will lead to an anti squat situation or the forcing of the wheel to the road surface under hard acceleration. if the swingarm pivot is placed too low this can produce a squat situation or the lifting the rear wheel off the road surface under hard acceleration. the Ideal placement will allow the swingarm to pivot freely under hard acceleration. most motorcycle pivot arms are placed properly. If changing ride height by shortening or lengthening the shock length, keep in mind the effect it may have on how the swingarm funtions during hard acceleration. if dimension A in this diagram is too high the swingarm will be forced down under power. If dimension A is too low the swingarm will be forced up. if things are properly set the swingarm can move freely under acceleration and braking." -Jewel Hendricks, Superbike preparation
I would add that you can change the effective length of your shock under compression (you sitting on it) with preload, this is another product of setting your rear sag, though once your sag is set you should use a ride hieght adjuster. Also keep in mind that the size of the sprocket can change the squat characteristics by changing the chain line.
This was also in Jewel Hendrick's book
Some basic ideas for ride height adjustments: If you are getting lots of "push" (slowly sliding front tire) put a little more weight on the front by lowering the front of your bike or raising the rear. If you are having rear traction problems, lower the rear or raise the front. Try to split the adjustment between the front and the back (ie: if you want to lower the front for traction by 10mm, lower the front by 5mm and raise the rear by 5mm) so you have more room for adjustment later and also so you have better cornering clearance.
If you want your bike to change directions with less effort, lower the front or change triple clamps to a tighter (closer to 90*) rake angle. Always pay attention to ground clearance and fork travel, don't make huge changes all at once, and only make one change at a time
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One more silly tip: You can add a bit of rider weight on/off the front by simply raising/lowering the handlebars. You should only put as much weight on the bars as is necessary to turn and you should hold your body weight with you legs and elbows, but you still have to lean to reach those bars and that weight still transfers. I turned my old Gixxer into a streetfighter and had to completely change the fork and shock in order to get the thing to stick, the front was very light and the rear was squatting badly, all from a handlebar change!
Wayne Rainey was another of the dirttrack refugees. He was teamed with Eddie Lawson at kawasaki and when Eddie went off the Europe,Wayne won the AMA superbike title on a GPZ750, then Kawi shut down their superbike effort so Rainey went to Europe to Race 250gp, Then he returned to the states and won an AMA championship for Honda before going to ride for Yamaha in the 500cc world chapionship. Wayne Rainey won the suzuka 8 hours for yamaha as well as the 500cc world title in '90,'91,'92 before he was paralysed at misano while in the lead of the race and the 500cc championship in '93. Wayne Rainey finished on the podium in 64 of his 83 starts.