sorry dude, but there is no definite answer to that one. EXCEPT...
lots and lots of PATIENCE!!!

you can put a cheat to get all orbs i did a cheat and i unlocked all secretz bro ok at the gameplay press select then:up up left right then boom u unlock ery secrert :)

It iis easy. get skull gems. go to a statue with blue eyes.he makes you do a hard race.
then he gives you orbs.p.s. ther every where.p.s.s there diffrent ones in the desert that
you need a car.p.s.s.s there some in the top of buildings.

Does that code work?