Hyosung GT250R mods on a budget

[sapperj]

I'll be installing my K&N High-flow (picked it up off trademe, cost $105 though) tonight and chucking in #100 front/rear main jets. I'll let you know how it rides when I've had a bit of a play.

I will be looking forward to hearing about your 'tune up'

Oh DB, I had a look at the front exhaust pipe where it goes into the collector, man it looks like it chokes up real bad there... like 20mm. Didnt notice if the rear pipe does the same but I havnt looked either. I wonder if that reduction is there to provide adaquate back preasure regardless of what muffler is fitted?

[Hiflyer]

20mm is sweet for a 250 man chuck a screaming demon exhaust on and it'll make it a bit perkier and sound so sweet! Jetting it doesn't make much of a difference, my mates GT250 was only a tiny bit faster off the line and up to say 80km/h over that there isn't much difference.

[vindy500]

screaming demon vs cycleworks?

[sapperj]

screaming demon vs cycleworks?

I went cycleworks.... they are local and NZ made. Plus cheeper
In saying that I bought the alloy one, there stainless cans are about 4 hundy

End of the day it is a straight through system and sounds awesome, as I'm sure any good open pipe would.

[Hiflyer]

I went cycleworks.... they are local and NZ made. Plus cheeper
In saying that I bought the alloy one, there stainless cans are about 4 hundy

End of the day it is a straight through system and sounds awesome, as I'm sure any good open pipe would.

"carbon fibre look" rules! haha I had a carbon fibre shorty on my old bike and it sounded excellent. And yes you wont find much of a difference, especially in 250cc bikes.

[CookMySock]

Hyosung FTW!






Steve

[sil3nt]

I test rode a GT250R the other week. I liked everything except the engine. It was rather dull and boring. Never really felt like i was going anywhere. Made a lot of weird noises as well. I would rather my GPX engine in the hyosung frame No one had a Ninja 250 for me to try out so i can't compare

Suspension and brakes were amazing compared to my GPX.

[CookMySock]

Ride one with a shorty screaming demon on it.

Steve

[wanpo]

Yo,
Reporting back. Was my first outing underneith the gas tank (Stupidly I filled it up on the way home that night >.<).
Removed airbox, tested the fitting on the K&N-0990, fits like a glove. Took off carbs and drained them of petrol. Replaced the 92.5/95 main jets with 100/100s. Reassembled everything, all up took maybe 2 hours tops.
Came to the moment of truth and the bike just wouldn't catch, was getting a little worried, after turning the engine over for maybe 1-2 minutes it sprung to life (Had me going for a bit.) Had a bit of a rark with it parked there, didn't sound or feel to different to what it did before... until...
I took her out for a test ride, sounded the same from no-1/2 throttle but as soon as the main jets start spraying she sounds like a demon out of hell. Instantly fell in love with it. Can't even hear the exhaust noise for the induction roar (I've got an aftermarket Scorpion muffler on there.)
Sounds aside, it's like everything's kinda shifted up a gear, pulls quite hard all the way up to ~130 in 4th gear, so that 5th actually feels like an overdrive gear (with power if needed.)
Might be running *a little* rich, as sometimes when I stop at the lights after a play I'll get a faint smell of petrol.
Only down side to it I've noticed is that I've had more troubles starting it, whereas it would start straight off no choke or throttle before, it has a little bit more trouble now. I might chuck in a pair of Iridium sparks in there to help ignite, or even try changing petrol (I'm running 98 which is probably a little bit of over kill >.>)
I havn't noticed any difference in Fuel efficiency; I'm up to 300+km at the moment on the same amount of fuel as I'd normally chuck in (and this is after a bit of it leaked trying to get the fuel tank off)
It didn't change the initial acceleration from stop noticably, not sure what to do to increase this, I think I'll try a port and polish when I get some time/bravery. That and possibly changing the needle.
Air filter is still just sitting unprotected ontop of the carbs, I tried modifying the intakes into the airbox so I could fit the filter inside it, but this didn't work too well; I'm going to have to cut a filter shaped hole in the bottom of it and just slip it over the top. (Will make for an easy removal if it changes the sound/power at all for when it's nice weather
If anyone's got any further questions on how it rides let me know, or if you're in the auckland region I'm always keen for a ride up Sh17 / a Ridge Road pass

[sapperj]

Wanpo, I cant wait to get my jets tomorrow... It sounds like you did not adjust needles aye.
And I see you put 100's in both cylinders. Have you looked at the plugs since re-jetting?
I was going to go 97.5 - 100 as that is what I have ordered, in keeping with the factorys set up.
Keep riding and we can compare results... Jas

[wanpo]

I lurked on the korider forums quite a bit and they seemed to say for aftermarket muffler/air filter that #100s was the way to go for both, but 97.5/100 would make sense as well. Main reason I went for the double 100 was because the place I got them from didn't stock anything smaller >.> I havn't checked the plugs yet, will probably be chucking in iridiums soon, might see what they look like then. If anything I think it is still running a little rich.
Yeah I havn't touched the needles or pilots, don't know too much about them tbh >.> with the needle, moving the C-clip closer to the tip would make it run richer? (i.e. shimming richens rather than leans out)

Oh and I lost one of the rubber bungs that the fuel tank slides into >.<

[sapperj]

... at least your honest. HTF can you loose one ot those rubber bungs? unless your garage is a total mess lol, not that mine ever gets that way

I will pick up my 97.5/100 today... might start on 95/97.5 and take it for a run, check plugs etc... dont want to be too rich either. But lean is worse!

Keep it between your legs

[wanpo]

I think the main problem was that I didn't notice when it came off, Garage is clean as and it's not hiding in the fairings as far as I can tell. Asked how much on trademe to some dude scrapping his Hyo >.>

[sapperj]

Man I get pissed when bike shops jerk you around... Ordered my jets by the Mikuni part number and only 1 arrived... the shop rings there supplier and are told the other one is not listed... shop looks on their online cataloge and tells them it is... parts guy says 'oh yeah, there it is'... will send it out on overnight courier.
SO I have to wait another day cause of their fuk up.

Not to mention another local bike shop who also are the main seller of Hyo's... cant even order the jets because they dont know what they are!!!!!!

How do these muppets even stay in buisness?

Thank god for 'google' and 'this forum' and other actual riders who know shit.

[gatch]

Yo,
Reporting back. Was my first outing underneith the gas tank (Stupidly I filled it up on the way home that night >.<).
Removed airbox, tested the fitting on the K&N-0990, fits like a glove. Took off carbs and drained them of petrol. Replaced the 92.5/95 main jets with 100/100s. Reassembled everything, all up took maybe 2 hours tops.
Came to the moment of truth and the bike just wouldn't catch, was getting a little worried, after turning the engine over for maybe 1-2 minutes it sprung to life (Had me going for a bit.) Had a bit of a rark with it parked there, didn't sound or feel to different to what it did before... until...
I took her out for a test ride, sounded the same from no-1/2 throttle but as soon as the main jets start spraying she sounds like a demon out of hell. Instantly fell in love with it. Can't even hear the exhaust noise for the induction roar (I've got an aftermarket Scorpion muffler on there.)
Sounds aside, it's like everything's kinda shifted up a gear, pulls quite hard all the way up to ~130 in 4th gear, so that 5th actually feels like an overdrive gear (with power if needed.)
Might be running *a little* rich, as sometimes when I stop at the lights after a play I'll get a faint smell of petrol.
Only down side to it I've noticed is that I've had more troubles starting it, whereas it would start straight off no choke or throttle before, it has a little bit more trouble now. I might chuck in a pair of Iridium sparks in there to help ignite, or even try changing petrol (I'm running 98 which is probably a little bit of over kill >.>)
I havn't noticed any difference in Fuel efficiency; I'm up to 300+km at the moment on the same amount of fuel as I'd normally chuck in (and this is after a bit of it leaked trying to get the fuel tank off)
It didn't change the initial acceleration from stop noticably, not sure what to do to increase this, I think I'll try a port and polish when I get some time/bravery. That and possibly changing the needle.
Air filter is still just sitting unprotected ontop of the carbs, I tried modifying the intakes into the airbox so I could fit the filter inside it, but this didn't work too well; I'm going to have to cut a filter shaped hole in the bottom of it and just slip it over the top. (Will make for an easy removal if it changes the sound/power at all for when it's nice weather
If anyone's got any further questions on how it rides let me know, or if you're in the auckland region I'm always keen for a ride up Sh17 / a Ridge Road pass

Yes, try a tank of 91. The octane number refers to its "anti knock" properties, you want to be running the lowest possible for your state of tune. If you advanced the timing somewhat then higher octane fuels will start to be of more benefit. 98, av gas etc..