I think it's Gen. I, so Dragon Rush doesn't exist. Otherwise, get Outrage, Dragon Dance, Dragon Claw/Dragon Rush, Aqua Tail/Wing Attack. Mine in Diamond works wonders with these moves. I beat Cynthia's Garchomp up with two DDs and a Dragon Rush. Both times Chompy used Dragon Rush, but missed. Mine was lucky and it hit.
Anyway, for Pinsir
If it's Gen. IV (I only try to do this for IVs because I don't own R/B/Y anymore and can't remember at all)
adamant/jolly @Salac Berry/Leichi Berry
Guts (or whatever it really is: I don't personally ever use Pinsirs so...)
252 Atk./252 Speed, 129 Speed/129 Atk., 129 HP
Flail/Close Combat (I think it can learn it)
Yeah. I suck at rating Pinsirs because I never use one, but try this. The first two from the first set is godly according to a lot of raing center people who actually had Pinsirs. Revenge is for... revenge, and X-Scissor's for good old STAB.
Charge Beam/Roost/Extrasensory (third one if you got Zapdos from XD)
I didn't get one from XD, so I have one with the first set, except my nature was Naive. It's really awesome!
Jolly @Muscle Band/Choice Band
252 Atk., 129 Def., 129 HP
Vital Throw/Cross Chop
I don't personally use Machamps, but I heard it from somewhere that Substitute+Focus Punch is the best moveset for a Champ.
Mild @Charcoal/Charti Berry (was it charti that reduced SE Rock?)
That's what I have on my Emerald (Gen. III) and it's the best substitute for my Torchie (Blaziken) and Melody (Altaria) combined.
Um. I think it's getting a little long, so I'll leave this like this.