The PROS.....I use the term loosely, want you to think that you cannot make stock components work well. All of the Black Art of suspension adjustment and customization is schrouded in Mystery. Racetech has removed some of the veil of secrecy and taught some of the masses. This does not sit well with other suspension guys who are trying to make a buck. Oh well.
Can I ask what "pros" are you referring to? Qualified suspension/geometry tuners will give you an explanation why they are going a certain direction. People who throw smoke and mirrors and wont explain in depth probably don't understand the philosophies behind it. As LDH said, its math and physics, and understanding cause and effect.
The other thing people may want to think about is you upgrade components ALL THE TIME, why does suspension get put in a different category? So I ask you (rhetorical, not directed at anyone particularly)
Why don't riders use OEM tires and play with pressures to get them to work well?
Why do you change stock exhausts out, why not play with the OEM exhaust to get it to work/sound better?
Why change out master cylinders? Brake pads, flash ecus etc?
We do this to get better performance out of a motorcycle. I dont think LDH is saying don't modify your OEM suspenison, but what he is saying is it's not worth his time. And honestly I agree with him. I dont revalve shocks either, its a waste of the riders time and money compared to upgrades. And depending on the rider, i dont revalve OEM carts either. And heres why...
1.OEM shock bodies are mass produced and use lower quality materials then aftermarket (a.m.) So this means there tolerances arent as tight and they wont dissipate heat as well causing shock fade earlier.
2. Revalving a shock is like putting a Mustang engine in a Pinto. Yes the valving in the shock is better, but you're still working with weaker components. So you'll NEVER get the same performance as an A.M. shock.
3.With the exception of the new R1 OEM shocks dont have ride height adjustment, SO making geometry changes is MUCH harder then with an A.M. shock. This WILL play a part in your riding as you progress and get faster.
4. We are constantly repairing A.M. shocks for various reasons. The beauty is we can order individual parts and get the rider back on the street/track in no time. Most of the time repairing OEM requires us to find a donor shock and it becomes more expensive to fix.
5. Riders can find trackside support and springs/parts for AM components vs a resprung fork or shock. And swapping out springs is MUCH faster and easier.
6. Most of the time you can get 70 to 90% of your money back if you sell off your carts or shock. Basically a revalved fork or shock is worth no more than a 100% OEM component.
I can go on and on, but you get the point. I like to refer to suspension as the redheaded child of the motorcycle community. People bitch and complain about upgrades but wont hesitate to drop major coin on a shiny exhaust or kill multiple sets of tires and then shake their head as to why.