Recently had to remove and strip engine to fix a broken 5th gear.did a lot of reading up on this mod and thought "bugger it",I will get hold of a cam and see how it goes.if I don't like it I can sell it again.the result is very good.seems to have better acceleration everywhere.even top ,as well as bottom.the bike lifts so much easier than before.i could usually accelerate up to 100 kph and pull real hard on bars to lift it up in 5th.now it is so much easier to the point that I sometimes have to check I am not in fourth lol.thats not using clutch BTW.the only drawback I have found is won't start with elec start anymore,but I don't care as all I do to start is give two twists of throttle ,no choke ,and it starts first kick cold.also first kick when hot ,without touching throttle or choke.the other drawback is more wheelspin,despite having brand new tyres.but using more finesse will overcome that. I won't be taking cam out lol. Bike is 04 wr 450 ,all free mods,o ring mod,yz 450 full exhaust,yz450 camshafts. Gearing is 15 /37. If you have been thinking about it.JUST DO IT!