x

[TadMC]

x

[RVertigo]

Put a GS500 sticker on a 'busa.

[Jake D]

Graft on an aluminum sub frame from another bike.  Not by welding, but fashion a system whre it bolts on.
Also, upgrade the wheels to Magnessium or Carbon Fiber.
Don't forget a carbon fiber gas tank and a Ti exhaust system.  After that, use an aluminum swing arm off another bike (no model suggestions here). 
Re-jet, drop ins.  Get a four valve head and do the 550 cc pistons swap.  Advance the timing. 
Upgrade forks to a USD set. 
Get Vortex clip ons, Wood craft rear sets.  Ditch the center stand and side stand and get spools for the rear swingarm and a bike stand. 
Dude, that is all I got.

[Codger]

It depends on how long you expect it to run at that P/W ratio.
The less time you need the easier it is.

[RVertigo]

Put a pirate bike engine in a GS.

[TadMC]

x

[Jake D]

Maybe 50 or so. 

[TadMC]

x

[TadMC]

x

[Alphamazing]

The best way to get the GS to have a better power to weight ratio is to lose weight yourself.

Fatass.

[rangerbrown]

true that

[pantablo]

aluminum spondon frame.

rgv250 swingarm...

[scottpA_GS]

NOS 

[Dr. Love]

Rolling chasis + RATO 

[CirclesCenter]

Take the entire engine.

Rip it apart.

Bore and stroke it to 632cc

Put in:

Forged Sleeves
Forged Pistons
Forged Con rods
Forged Crank

Place GSXR 750 head on top with requisite porting/polishing and UBER camshaft
Use those uber bolts they sell for aircraft use

Apply atupid sized carbs and NOS. Lots of nos, like a 75 shot, or hell even a 100 shot.

Carbon fiber/ aluminum EVERYTHING.

Don't bother with an exhaust, open headers. (Weight savings!)

Remove seat/plastics/lights

Remove starter and use an external like a drag racer.

Remove entire rear subframe and learn to stand and ride.

Also remove kickstand.

[werase643]

just a FYI
a RS125 GP racebike is 45-50 HP and 165 #
better to spend 10 K on one of these.....frigging AWSOME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[LimaXray]

Or you could just slap on a turbo and run it on ethanol or race fuel... 100+ hp would be super easy, maybe not super reliable, but assuming the bike weighs 400 lbs that'd be a .25 power to weight ratio.

Someone bring me your GS, I'm gonna turbo it

[CirclesCenter]

Would you supply all parts and labor?

[TadMC]

x

[CirclesCenter]

Or you could just slap on a turbo and run it on ethanol or race fuel... 100+ hp would be super easy, maybe not super reliable, but assuming the bike weighs 400 lbs that'd be a .25 power to weight ratio.

Someone bring me your GS, I'm gonna turbo it

if money wasnt an issue, you could get the whole engine made of titainium... that would help the reliablity, maybe

I prefer...

UNOBTAINIUM