Bugsy? Pretty easy on Gold/Silver and their remakes...
Gold/Silver/Crystal: Metapod is just annoying and will PP waste you some turns, just use whatever thing who doesn't care about String Shot and the PP lose. Kakuna is almost the same, but you'll gonna have to waste maybe an antidote if he poison your Pokémon early, when Kakuna is almost defeated, change to your favorite bird/rock/electric Pokémon, or just to your Cyndaquil or Totodile (if you choosed Chikorita, just use the others types already mentioned), Scyther have great attack, but he doesn't have attacks to use it at all, he'll spam Fury Cutter until it reaches to unstopables levels... of course, this battle is actually easy if you have a Super Efective attack, or just a Pokémon who can handle him's first Fury Cutters and deal good neutral damage (Totodile), pretty straightfoward. If you don't have the correct types, you can still use an X-Attack and try to get rid of him with whatever neutral damage, him's Fury Cutter will not reach to usable levels until 3-4 turns, you have the time to set up and get rid of him, and even if he reachs to powerful levels of Fury Cutter, Onix can still wall him all the day (Geodude can, too, but he may have problems and you'll need more potions in that scenary).
Remakes: Now Metapod can't stall your PP. When Metapod is on the field, just set up whatever you want if you have a set up move or have the X-Items; if the answer to boths are nope: Then just get rid of the Metapod fast. Against Kakuna just have some Antidotes for the possible Poison, but now Kakuna can't stall your physical attacks without Harden, so, that's not too much probable, Zubat/Beedril/Gastly cannot even being poisoned, if you're having troubles of money.
Finally, Scyther, he's really excesive easy to beat, he's the same as before, but now have Sitrus Berry, changed Fury Cutter for U-Turn, and have Focus Energy, well, U-Turn is a lot easy to manage than Fury Cutter, actually, Fury Cutter can reach to 160 of power if you're not having the enough raw power to stop it before, but U-Turn can't just increse it's power, 70 + Stab is good, but any Pokémon with decent defense can resist 1 (or even 2) rounds and destroy him with any super effective attack. Geodude and specially Onix can wall him all the day and give him back a wonderful Rock Thrown (Scyther is x4 weak to it), Cyndaquil can resist 1 U-Turn and give him back Ember, Pidgeotto can resist him without any trouble at all (2 or even 3 hits) and just destroy him with whatever flying-type attack, Zubat can wall Syther all the day with him's x4 resistance to U-Turn and just ate him with Wing Attack (or Bite if you're low leveled). Even Gastly can resist 2-3 U-Turn with him's double resisntance and just Curse Him if Kakuna and Metapod are out from the battle, or just spam Night Shade.
Actually, Scyther is just a problem if you're not carring anything who can resist bugs attacks, or can give him back a super-effective. Fighthers, Fire, Flying, Ghost, Poison, (and steel) resist him's U-Turn. Fire, Flying, Electric, (Ice), and Rock (x4) can strike him back with super-effective. If you're not having any of those defensive or attack types, your team sucks as hell.