Sup up a Suzuki GN 250 engine

[guest1406]

Hi there, this is my second post on this forum. My first forum was about my van van, which members very wisley helped me realise a few things. I have a project with my van van as this is all i can afford at the moment and its a keeper as it will be my first project. My aim is to strip it of all things unnesesary and have it as a bare minimum required bike (i.e. just want engine, frame and wheels, no fancy stuff), similar to a wrench monkees bike. I will post some pictures of the mods when i can fine my camara lead. So far i have put a 92' GN 250 tank, unpainted with dents (i like that look :/) and had the seat chopped and thinned as much as it could. next is to take out the side panels.
Anyway, what i do need is info on the GN250 engine as that will slot in to the frame as a stressed membrane (will not ever get a stressed membrane frame from a project bike again!). ive read quite a few things on it on this site and a few others but i would like definiate answers from people who really know there stuff. How can i sup un the gn250 as much as possible while keeping it road worthy and not killing it. I know you can bore, change carbs, rejet and do a few other things but thats all i know, so i would need names/types of carbs i could use etc. For anyone who wants to know ive read these following things:

http://answers.yahoo.com/question/index?qid=20071215171328AAUnnqi

and

http://www.kiwibiker.co.nz/forums/archive/index.php/t-9795.html

Thanks for any help, it will be honestly much appreciated

[guest1406]

Also, im really sorry, but i would love it to be a kickstart, is that possible?

[SteveC#222]

To be honest you could easily end up spending a lot of money for not a lot of gain and quite possibly a less flexible, unreliable engine. The GN250 engine is pretty 'buzzy' anyway ( at least in the standard bike) and once you start chopping and changing carbs, cams and pistons you need to know what you are doing.  Good luck with your project!

By the way, keep a close eye on the oil level, GN's drink oil like an alcoholic in a brewery!!!

I don't think you can retro fit a kickstart...which is a real pain.

[guest1406]

Hi Steve, yeh I see your point. I do think it could slightly be possible to make it slightly better and keep it reliable if i just dont go nuts. Ive heard that they drink oil quite a bit, I will keep my eye on that thanks. Theyre said to have 22bhp which would hit around 85ish mph? According to one guy he says:
Stage 1:
A good exhaust system, high flow air filter and carbs jetted to suit. estimated gain over standard = 3 HP

Stage 2:
Cylinder head porting and raise compression ratio + stage 1, estimated gain over standard = 5HP
 
Stage 3:
Big bore kit + stages 1 & 2 estimated gain over standard = 8HP
 
Stage 4:
Better carburator + stages 1,2&3 estimated gain over standard = 10HP

How much of that is true?
 

[guest295]

Not much. If you had unlimited funds and loads of experience and lots of spare time and all the special tools, you could get that sort of power but the engine would have a very short life. Why bother? For far less money you can buy a whole Kawasaki Sherpa or similar and it will run for years.