How to create a fire breathing GN250

[Coyote]

Rip the motor out, replace it with a GSX1300R motor, then add a twin turbo and intercooler, nitrous, and fill the tank with a kerosene/nitro methane mix

[Coyote]

Oh, and also add 20" Chrome spinners and a big bore exhaust, cause obviously, they are the only things needed to deem it a high performance bike

[Ixion]

I'd suggest going for 28mm Id headers of the same curve /length as stock and feed it back into reverse cone megaphone

Yep, 4 stroke single, reverse cone mega has always been the way to go. Just be aware that depending on the reset of the setup (cams, carbs, timing) you may find it's not much cop at lower revs. Which sort of defeats what a GN250 is all about. Sounds nice though.

[cowpoos]

exhaust science huh....well....why has know one asked the obvious questions an exhaut tuner would ask or find....

what Cfm will the head flow at peak rpm...with airbox/filter/carb attached
what is peak engine rpm
what are the cams profiles
dialed is at?
engine working temp range/peramiters
CR?

[nudemetalz]

Why don't you get an NZ250 engine for it?
Puts about 34hp, 6-8 more than the GN already, before you even think about tuning it.
Based on a DR so very bulletproof. The only thing you'd need to do is hook up an oil cooler for the cooling, but that shouldn't be a big deal.

The NZ's no slug for a 250 single, so would think that all that tuning would only bring it up to NZ-250's levels anyway.

Cheers
Chris

[ducatilover]

Why don't you get an NZ250 engine for it?
Puts about 34hp, 6-8 more than the GN already, before you even think about tuning it.
Based on a DR so very bulletproof. The only thing you'd need to do is hook up an oil cooler for the cooling, but that shouldn't be a big deal.

The NZ's no slug for a 250 single, so would think that all that tuning would only bring it up to NZ-250's levels anyway.

Cheers
Chris

if your lucky. why dont i just stick my fucken gpz400r enjine in mine? i fixed its gear box today

[The Pastor]

Just nos the basterd, cheap and easy to do, and biggest hp gain, albeit for a short time but you did just want it to pass the slow twits right.

[peanuteater]

From memory, just shove in a suzuki dr 350 motor, just pops straight in-cheap, quick and easy !!, then add nos, turbo etc-seriously tho, they fit the mounts etc !

[Titanium]

All sounds fantastic if you want a lifetime of wrenching on a bike instead of riding it.......

Why not just get a bigger bike?

[degrom]

Best mod for the buck is a 280 big bore if you can still get 'em.On a single a megaphone is the best thing you can do on the exhaust,with a reverse cone,way better than a straight pipe,and twice as loud.Bigger carb and a hotter cam.

Is this true? Can you get this? And what is part of the kit?

I just hope that it won't replace the 250cc indicator in the motor for L-Plate riders... LOL

[kro]

Don't mock the mighty GN, a large portion of its engine parts can be used in a DR 250.

[MikeyG]

Barrel and piston from a GN400. The 249cc stamping is on the block so with the new barrel and piston the it will still look like a 250

[degrom]

Barrel and piston from a GN400. The 249cc stamping is on the block so with the new barrel and piston the it will still look like a 250

I think you might need a GN400 head then?!?

[degrom]

What kind of improvement will you see if you make the cam a bit hotter?

[mokr]

a gn250 should do 140 down hill.
and at least 110-120 on the flat.
or the engine is stuffed.

i wouldnt bother putting cash/effort into the engine unless ure really bored
its air cooled so there are big gaps in the engine for the heat expansion
so its never gonna be a big rever. a 500 or 600 air cooled is still not big horeses but they do haul ass, my tt600 single pulls hard up till over 180

if u want a fast bike get something else. youll spend heaps of cash on it and it will just cook the engine.

keep checking the oil and be happy with the gn for a cool cheap runner.....maybee do the pipe