Mods thread: Hyosung GT250R

[Gubb]

Never cut. Disconnect. Don't do anything you can't reverse in 5 minutes.

[wanpo]

What Tires are good to chuck on the GT250R?

my shitkos are reaching the end of their (short) lifespan, ~11k km

[Gubb]

BattleAx

10motherfuckin'char

[kolio]

hi!
i am from ukraine. I have hyosung gt250R 2006 year and i have some problem on 3-third step on 5700 rpm
2 hours ago i disconect green-bkue wire and after work i will try modification

YYESSSS!!! I HAVE NO PROBLEM ANYMORE WITH 6000rpm. ENGINE IS A ROCKET


but my friend have this problem and he not have green-blue wire on CDI. he have old old CDI ? we dont understand what do with hes CDI

[325rocket]

Go here and see if you can make sense of it then try it out in a way you can easily repair if your guess was wrong. I haven't done it on mine yet cos it seems they wired the bikes with spare parts from uncle bob's rainbow wire shop and all the looms are a combination of colours etc. There are some pic's there of the "black box" plugs but I haven't had a look at mine to see how it all lines up.

DONE !!! its about a 2 minute job and has sorted all my "unpredictable" cornering issues. before i had to feather the throttle to get back on the gas now its smooth as...

[Pancakes]

..........................So in short, the GT250R's gear ratios wont allow these great speeds people always seem to talk about


Sucks eh

Thats the first thing I though when I read the AMAZING speeds people were posting on stock Hyo 250's. Thats a few grand over redline and a loooong road with the top speed trade off with accelleration.

You would need to be doing something real wrong for it to fuck it up catastrophically, will probably just run a bit dodgy...........................................

Running lean and overheating the exhaust valve stem coupled valve bounce when they are over-revved with soft valve springs (and they must be looking at the torque curve on these, they are made for low efficiency not top end) will see the valve head in the combustion chamber in the near future. Haven't heard of it on a Hyo but thats how you mod and kill a bike.

Sounds like the bizzo GN FilthyL, way ta go!

[FilthyLuka]

Running lean and overheating the exhaust valve stem coupled valve bounce when they are over-revved with soft valve springs (and they must be looking at the torque curve on these, they are made for low efficiency not top end) will see the valve head in the combustion chamber in the near future. Haven't heard of it on a Hyo but thats how you mod and kill a bike.

Sounds like the bizzo GN FilthyL, way ta go!

Cheers

I know bout the running lean will cause all sorts of nasties, but surely that extent of lean-ness (is that the term im lookin for? something like that) wont be caused by a replacement air filter and a free flow pipe?

Oh, and dude who started this thread whose name i can't remember because the back button is all the way up there, i know a guy out in henderson called warren bridges, the guy is a master with carbs, PM me if you want his number. He doesn't charge an arm and a leg either

[Pancakes]

Cheers

No worries, sounds like you've done enough work to deserve a "nice one"!

I know bout the running lean will cause all sorts of nasties, but surely that extent of lean-ness (is that the term im lookin for? something like that) wont be caused by a replacement air filter and a free flow pipe?

I wouldn't say that it WILL happen but with the power difference you can get from those mods to a Hyosung and that it is still a small bike so sitting on redline at WOT is still very likely I think there would be a really good chance the heat stress would get that high.

Oh, and dude who started this thread whose name i can't remember because the back button is all the way up there, i know a guy out in henderson called warren bridges, the guy is a master with carbs, PM me if you want his number. He doesn't charge an arm and a leg either

PM sent also, I need to get the carbs done in mine so I can start using the straight pipe.

[streethot]

Hi there.....I am from brazil and there are a good qtd of gtr250 over here.....

i am looking foward to improve performance......i know its easy to buy a new bike.......but I likey to put my hands on the work.....all my cars have mods....

i have done so far:
1)carbon exhaust
2)cut wire on the cdi

what i am developing
1)new air filter
2)jetting

we dont have jet kits like that on ebay......but we figure it out with parts from other carbs......

someone have done some head porting on these motors?

[streethot]

and.....

the vaccum that pull fuel pump came from one intake (rear intake), i wonder if i put a " T" conection to pull from both intakes would be better for fuel balance......or it could do any good at all?

[DangerousBastard]

and.....

the vaccum that pull fuel pump came from one intake (rear intake), i wonder if i put a " T" conection to pull from both intakes would be better for fuel balance......or it could do any good at all?

No, that hose only opens the fuel valve on the tank.

If you want to go faster, the best mods to do on the GT250R is front and rear suspension. Most of the problems with the GT250R are because of its bumpy ride in corners. Change the rear shock and fit cartridge emulators to the forks.

Steve

[streethot]

Can anyone tell what jetting and carb settings are you using with mods like muflers and new air filter.....?

[DangerousBastard]

Can anyone tell what jetting and carb settings are you using with mods like muflers and new air filter.....?

I just put a two inch straight-through muffler on, and with the jetting standard it's slightly harder to start cold or hot (needs a blip of throttle.) Also the tailpipe is running VERY clean. I think it's a tad lean, so I'm going to get it checked on the exhaust gas analyser and maybe raise the needles with the clip or a shim. I'm not trying for more horsepower - just trying to make sure that the engine is not harmed.

Will report back.

Steve

[streethot]

just tested on street.....

new jets
hi flow air filter
carbon exhaust
wire mod

nice ride......12k rpm easy......could use more advance or something......

on downtown streets only went to 3rd gear at full throttle.....

i am one more very happy GTR250 owner!!!!!!!!!

[woodhillkamikaze]

I had my blue green wire pulled out and then realised that the bike performed better with it in. Talk to the guys at Mt Eden Motorcycles (they are Hyosung Dealers) they'll confirm that pulling the wire out is BS. It goes better the way they built it!