Hyosung GT250R mods on a budget

[Filter_nz]

Ok I've reading through the legnethy thread on Hyo 250 mods and even posted what I've done, and I've done quite a bit. To simplify for others and cut thre rubbish out this is all you really need to do...

1) Exhaust
either
a) Either debaffle the stock with (with a massive long drill bit)
or
b) Order yourself a Screaming Demon pipe off ebay in OZ for about $300-$350 inc shipping. You can get them on TradeMe but they're a rip off, import your own it's easy. You can also fit these yourself in 15mins

2)Intake
either
a) Modify the stock airfilter (cut the tiny circular hole so the size of the entire oval. Easy-peezee, you'll see what I mean when you take the tank off.
Will take about 30-45mins all up.
or
b) Buy a aftermarket DNA/BMC whatever.. IF you can find one

3)Jets
Yes jets... we've all heard doing the filter and pipe will run the fuel lean and pop when backing off the throttle. Ignore all the rubbish about rejetting. All you need to do is take out the jet needles and shift the locator circlip one setting closer to the tip/point of the needle. This will richen you mid-throttle fuel mix... sure on full throttle you'll still lean out but the reality is 90% of the time you don't have the throttle all the way open. Rejetting is a waste of time and money. Do the needle yourself!!! takes about an hour if you're new to it... depending if you can get the screws out of the needle covers easy.

To sum up... on a budget...
1) debaffle, 2) mod the air box 3) change the needle setting

Anything more is a waste of money on a learner bike. These mods will extract a good amount of untapped power without costing much if anthing.

Also the CDI mod... search the forum for that one it's just a wire to pull out. 5 mins.



My setup

Exhaust
Screaming Demon can
-$330 off Ebay, custom made for me WITHOUT the SD logo riveted to the pipe.

Intake
Modified stock filter and box -$0
Cut the circular hole to the full size of the air box oval
I can't seem to source an aftermarket filter.

Jets
Jet kit brought off ebay from a tuner -$100
I upgraded my jets 95 to 97.5 and the second jet, 92.5 to 92.5
Upgraded my pilot jets
Moved the needle setting from the middle position to the 3 position (richer)

CDI
Removed the retard wire.

I would say with my setup at a guess I'm 8-10hp above the stock 28hp. The Hyo runs A LOT better, mostly mid ranger power however and now the bike will climb to the redline in 5th gear without much trouble.

[xwhatsit]

You can buy most sorts of jets for $7 each. If you're doing the needles, it's just a matter of unscrewing the old ones and fitting $14 worth of parts yourself. Not hard!

$100 for a `jet kit' -- mental.

[BadCompany]

...but the reality is 90% of the time you don't have the throttle all the way open.

On a 250? 90% of the time the throttle is always fully open. Unless your on a cruiser or a ZZR.

[Filter_nz]

Wow 2 nonsense replies already!

1) Rubbish that any 250 has the throttle open all the way 90% of the time. Only out of corners or off the line would this really be the case. If you bike can't hold its speed without having the gas full on shift up a gear.

2) $100 for the jet kit isn't the ripp off you claim. Included were the jets, the pilots, drill bits, anti-cam, instructions and of course postage from the USA. Not to mention the tuners time and efforts to figure out the right jets and positions for the tune. I doubt any bike shop would be that cheap er unless all they do is adjust the needles which is all I suggest you do any way.

[xwhatsit]

2) $100 for the jet kit isn't the ripp off you claim. Included were the jets, the pilots, drill bits, anti-cam, instructions and of course postage from the USA. Not to mention the tuners time and efforts to figure out the right jets and positions for the tune. I doubt any bike shop would be that cheap er unless all they do is adjust the needles which is all I suggest you do any way.
Not quite what I'm saying there. What I'm suggesting, is that one shifts the needles oneself, as you recommend. Pilot mixture can be taken care of mostly just using the pilot screw. What's left? Just main jets. And main jets can be bought for $6-$7 each. Seeing as there's only two of 'em, why not just buy $14 worth of parts and set your mind at rest? Especially so as you've kindly supplied the jet sizes for us that worked for you.

[BadCompany]

Wow 2 nonsense replies already!

1) Rubbish that any 250 has the throttle open all the way 90% of the time. Only out of corners or off the line would this really be the case. If you bike can't hold its speed without having the gas full on shift up a gear.


Haha you can't be serious? If I'm giving it a bit of stick (which I'm most often doing) then I'll have the throttle fully open until I get to near redline, change, throttle fully open, near redline, change and so on. Can you eve ride your 250 properly? Because it doesn't sound like it.

[Ragingrob]

Haha you can't be serious? If I'm giving it a bit of stick (which I'm most often doing) then I'll have the throttle fully open until I get to near redline, change, throttle fully open, near redline, change and so on. Can you eve ride your 250 properly? Because it doesn't sound like it.

So what happens when you get to the speed limit? Or corner? Or intersection? 90% of the time is a massive exagerration. Sure, compared to big bikes the 250s are open throttle out of every corner and when accelerating from stopped, but that is hardly 90% of the time.

[BadCompany]

So what happens when you get to the speed limit? Or corner? Or intersection? 90% of the time is a massive exagerration. Sure, compared to big bikes the 250s are open throttle out of every corner and when accelerating from stopped, but that is hardly 90% of the time.

Dude seriously c'mon, lighten, bend over and I'll pull the stick out ya arse. The '90%' was a piss take. But I do spent A LOT off time full throttle.

[Ragingrob]

Dude seriously c'mon, lighten, bend over and I'll pull the stick out ya arse. The '90%' was a piss take. But I do spent A LOT off time full throttle.

Then don't sound so serious when you suggest that he can't ride his 250 properly mate. A lot OFF time? Exactly.

[BadCompany]

Then don't sound so serious when you suggest that he can't ride his 250 properly mate. A lot OFF time? Exactly.

Haha I love how fucking critical people are on the internet, makes taking the piss out of them so much more fun.

[FROSTY]

Wow 2 nonsense replies already!
I get where you are coming from but you're wrong re the jetting.
2 Main jets up 10% are gonna cost $14.00 thereabouts.
taking your advice without changing main jets potentially costs $2500 or so
-Bike running lean say -Ohh I dunno auckland motorway
spends a lot of its time at 3/4 or more throttle.
+bloody big hole in (most likely) rear piston.
For the sake of $14 I'd change the jets.

For the record it isn't so much the off /on throttle thattle do it --its the looong boring straight bits.

[FJRider]

I get where you are coming from but you're wrong re the jetting.
2 Main jets up 10% are gonna cost $14.00 thereabouts.
taking your advice without changing main jets potentially costs $2500 or so
-Bike running lean say -Ohh I dunno auckland motorway
spends a lot of its time at 3/4 or more throttle.
+bloody big hole in (most likely) rear piston.
For the sake of $14 I'd change the jets.

For the record it isn't so much the off /on throttle thattle do it --its the looong boring straight bits.

Not changing jets is short time gain, long term is... costs money for rebuild when the fire goes out. Want more horsepower... BUY A BIGGER/BETTER bike.
Increasing horsepower shortens the "lifespan" with rebuild costs more than its worth.

[FROSTY]

. Want more horsepower... BUY A BIGGER/BETTER bike.
Increasing horsepower shortens the "lifespan" with rebuild costs more than its worth.
Point one--:headbang::headbang:totally agree
Point two-- nahh dude those hyusungs are pretty insipid stock.
Its almost as if theyve been strangled bigtime to keep the HP down
Normally I'd agree with ya but I suspect with the breathing freed up they would actually last longer

[Ragingrob]

Haha I love how fucking critical people are on the internet, makes taking the piss out of them so much more fun.

Sweet, well I'd love to know where those twisties are so that I can ride with my throttle fully open even half of the time :niceone:.

Oh, and let me know when you grow up too :2thumbsup

[NOMIS]

Reeeeeooowww:argue:

[BadCompany]

Sweet, well I'd love to know where those twisties are so that I can ride with my throttle fully open even half of the time :niceone:.

Oh, and let me know when you grow up too :2thumbsup

Who said anything about twisties? More like traffic lights after traffic lights.

Oh, and maybe next week, but then again, I have to much fun with people, so probably never.

[Ragingrob]

Who said anything about twisties? More like traffic lights after traffic lights.

Oh, and maybe next week, but then again, I have to much fun with people, so probably never.

Even on a 250, going by your 'riding style', I would be going 70 before I changed into 2nd gear... That's 20kph over the speed limit already... Maybe your bike has got something wrong with it if you can somehow almost red line before all your changes round town? Unless you're one of those 'temporary citizens'.

[BadCompany]

Even on a 250, going by your 'riding style', I would be going 70 before I changed into 2nd gear... That's 20kph over the speed limit already... Maybe your bike has got something wrong with it if you can somehow almost red line before all your changes round town? Unless you're one of those 'temporary citizens'.

Nah the set off lights I'm thinking of is in an 80k zone.

Also, you don't have to redline to go full throttle.

[Ragingrob]

Nah the set off lights I'm thinking of is in an 80k zone.

Also, you don't have to redline to go full throttle.


Haha you can't be serious? If I'm giving it a bit of stick (which I'm most often doing) then I'll have the throttle fully open until I get to near redline, change, throttle fully open, near redline, change and so on. Can you eve ride your 250 properly? Because it doesn't sound like it.

Oh ok, sorry I just thought that you said that for some crazy reason :crazy:

80k zone, sweet so you'll get in one gear change. Yep, you can sure ride a 250 properly :wari:

[BadCompany]

Also, you don't have to redline to go full throttle.



80k zone, sweet so you'll get in one gear change. Yep, you can sure ride a 250 properly :wari:

Swing and a miss.

[Ragingrob]

Swing and a miss.

Lol, sorry I don't see how. You clearly stated that you ride with fully open throttle and near redline then change up... Oh, unless the red line is just you having your period?

:Oops:

[xwhatsit]

Lol, sorry I don't see how. You clearly stated that you ride with fully open throttle and near redline then change up... Oh, unless the red line is just you having your period?

:Oops:
Heh, GT250 a little different from CBR250RR. GT250 more like my 250RS -- 26, 27hp, ~10,000rpm redline. So not much more than half horsepower of your bike, half the redline. 90% of the time at full throttle is certainly horseshit, but I spend a lot of my time with the throttle at 75-100%. 50kph means 3rd gear at least for me, GT250 guys would be similar (and don't they have 6 gears?).

Don't pick holes in the guy, he's a testosterone infused boy racer refugee, too much of an easy target :whistle: But once you get below the bluster and bullshit, what he's saying is mostly correct.


Anyway, that's not what the thread is about. Cheap Hyosung mods! We all agree to spend $14 on jets and 60 seconds extra time installing them then?

[CookMySock]

gee another thread in tatters because of trolling. Take a hint - if you just HAVE TO reply because it pisses you off, do it in their red rep, rather than in the thread. That way, YOU wont be contribute to said destruction AND they get the red rep - not you.

Don't feed the trolls !

DB

[NOMIS]

gee another thread in tatters because of trolling. Take a hint - if you just HAVE TO reply because it pisses you off, do it in their red rep, rather than in the thread. That way, YOU wont be contribute to said destruction AND they get the red rep - not you.

Don't feed the trolls !

DB

But then this thread would just be boring? would be about 3 replys long and would just come to a end .. Kinda like thoes movies when your real into it and it just ends when you least expect it not climax nothing! arrrggghhhh

but come on guys :Playnice:

[Ragingrob]

All good, well in terms of 250 mods in a kinda side not but on topic kinda way... I've drilled some holes just in the end on my can, between the baffle hole and the outer shell, and it sounds 100x better by just doing that! Takes 10mins and doesn't require any re-tuning of the bike.

Good post up of mods, makes it nice and easy for all those with a GT250r or any other bike for that matter to see what cheaper mods are out there!

[NOMIS]

Visual mod's??? Dont get me started there not cheap though.

performance mod's, well I was thinking bigger carb's from japan but soooo expensive for a gain of only 5-7hp

[CookMySock]

I've drilled some holes just in the end on my can, between the baffle hole and the outer shell, and it sounds 100x better by just doing that! Takes 10mins and doesn't require any re-tuning of the bike.Something, not sure what, just set my "assumption detector" off.

DB

[Ragingrob]

Something, not sure what, just set my "assumption detector" off.

DB

Regarding the re-tuning? Well your detector must be faulty, because I did my research and talked to people who know what they're doing, including someone who's drilled holes and even removed the rear baffle and dyno'd his bike before and after with no difference in results.

[CookMySock]

is the air/fuel ratio still the same as stock ? Is the EGT still the same front and rear ?

DB

[Ragingrob]

is the air/fuel ratio still the same as stock ? Is the EGT still the same front and rear ?

DB

I doubt that 20yr old bikes' ratios are still the same as when they came out of the factory anyway... Who knows what exact difference it's made in terms of performance but if it's done anything at all it is so minimal that it's unnoticable. I know for a fact though that it seems to idle smoother now so there's a pro for ya.

[NOMIS]

I doubt that 20yr old bikes' ratios are still the same as when they came out of the factory anyway... Who knows what exact difference it's made in terms of performance but if it's done anything at all it is so minimal that it's unnoticable. I know for a fact though that it seems to idle smoother now so there's a pro for ya.

yeh other wise your cbr should have been smoking my hornet. :-)

[BadCompany]

I'd be more worried about trying to pass a WOF with an exhaust that has wholes in it. Not sure about bikes (or where abouts you put the wholes) but cars fail on it.

[fizbin]

Back to the thread. is there anyone that can show me how to do some of this stuff. i have a bit of a shoe string budget and the sound of being able to get a few more pony's out of the gt250 sounds great!:scooter: As i am a fat bastard as some will testify to.:whistle:
What would you recommend i start with.
Can you re-jet with out doing the exhaust?
now play nice kiddies this was a sensible question if not a newbie one!

[Ragingrob]

I'd be more worried about trying to pass a WOF with an exhaust that has wholes in it. Not sure about bikes (or where abouts you put the wholes) but cars fail on it.

Well as I said, the holes are inside the exhaust between the baffle hole and the outer shell. Unnoticable unless you are looking right into the exhaust. So hopefully should be sweet, WOFs in the past the guys haven't even looked at anything mechanical at all, pretty much check it goes, lights, brakes, forks, tyres, done deal :Punk:

[Ragingrob]

Back to the thread. is there anyone that can show me how to do some of this stuff. i have a bit of a shoe string budget and the sound of being able to get a few more pony's out of the gt250 sounds great!:scooter: As i am a fat bastard as some will testify to.:whistle:
What would you recommend i start with.
Can you re-jet with out doing the exhaust?
now play nice kiddies this was a sensible question if not a newbie one!

You CAN re-jet without doing the exhaust. Correct me if I'm wrong though but I think re-jetting is done in order to re-tune the bike's engine for the newly done exhaust. So re-jetting a non-modded bike would only make it run rich or lean, whereas after you've done the exhaust then it would be correcting how it runs. I think... ;)

[CookMySock]

I'd be more worried about trying to pass a WOF with an exhaust that has wholes in it. Not sure about bikes (or where abouts you put the wholes) but cars fail on it.Grab the pop rivet gun and bang some rivets in them. All looks stock now. Total cost = seven cents.

DB

[Ragingrob]

Grab the pop rivet gun and bang some rivets in them. All looks stock now. Total cost = seven cents.

DB

Will keep that in mind if I have any trouble. Also I'm sure I could use some kinda sealant just to cover them up. It's so dirty inside the exhaust anyway ya can't see them :shifty:

[CookMySock]

You CAN re-jet without doing the exhaust. Correct me if I'm wrong though but I think re-jetting is done in order to re-tune the bike's engine for the newly done exhaust. So re-jetting a non-modded bike would only make it run rich or lean, whereas after you've done the exhaust then it would be correcting how it runs. I think... ;)Yes this correct. The free-er flowing exhaust reduces the back pressure on the engine. The result is less exhaust gas retained in the combustion chamber and carried over to the next cycle. This carried over gas is actually a good thing for emissions because it lowers the whatsits name bullshit thingy in the doodad mixture whatsit. Some shit like that anyway, but yeah something to do with introducing inert gas to the combustion process and helping emissions. Opening up the exhaust stops this from happening, and wrecks the nice clean green-ness of your bike whilst introducing more "grunt" in the process.. ie, the whole point to begin with. More fuel-air, less inert gas = more grunt. The trouble IS, the carby was never set to allow this, and now more air = leaner mixture ish, and you need to richen the mixture slightly lest ye burn yer valvies and ringies and stick them to other, or WORSE, burn a hole in yer flamin piston like frosty sed.

The short story is, if you drill a few holes so its a little bit farty you will prolly be fine, but if you open the bugger right up and do lotsa highway driving, you will (what we call it in the trade) "fuck it."


so, yeah.
DB

[woza]

did you intall the AIS kit it recommends?

[Filter_nz]

Back to the thread. is there anyone that can show me how to do some of this stuff. i have a bit of a shoe string budget and the sound of being able to get a few more pony's out of the gt250 sounds great!:scooter: As i am a fat bastard as some will testify to.:whistle:
What would you recommend i start with.
Can you re-jet with out doing the exhaust?
now play nice kiddies this was a sensible question if not a newbie one!

If you can't afford a new can take the stock one off and drill holes into the internal baffle at both ends, this will free it up and sound better.
I still disagree with a few posts about the jets. Perhaps on other bikes but the Hyos if anything seem to run a little rich stock. Dropping the needle setting is something you can do yourself and is the least you should do if you've done the filter and exhaust - you'll still lean out on full throttle but like I said, besides lights and corner exit's not full tap that often and I doubt you’ll do any damage.
After doing the filter and exhaust I initially was going to take my bike to TSS motorcycles in Lower Hutt but after talking to the mechanic he said all they usually do is adjust the needle and suggested they run fine without doing anything which I was a bit surprised to hear. They had a black demonstrator model with a cycle-works can with nothing else and they seemed to think it was fine.
The crabs are Japanese on the Hyo's at least mine is on the 07 model. The jets took 3 times as long to do as the needles and almost impossible to get at without stripping the screws and stuffing it altogether.
That said if you can buy the jet sizes I had for $14 and have decent tools go for it.
I might not be able to "ride my 250 properly" as someone said... however I've only just got my restricted, I'll get there.

[2wheelsbetterthen4]

You mentioned de-baffling the origional pipe using a big drill bit...
Does this just involve drilling straight down the middle of the pipe or what? And how big a drill bit?
Also would this make it sound better? or just make it tinny?
And do you think the bike would need to be re-tuned after drilling baffler and opening up airbox a bit?

Its just i can't see how me in my shed with a drill bit can make the bike better then a whole team of engineers at hyosung designed it to be...
thanks.

......
ok 4get i asked... that last post explains it. :)

[wanpo]

Sorry if this is reviving an old thread.

Just a question about sourcing the jets themselves; Where from and are they standard to all motorbikes? (the fit, not the value. I'm on a GT250R also)

I've got a custom tailpipe and am thinking about doing the intake mod to cram in more air.

Reading on the korider forums they seem to say change up to 97.5/100 or 100/100 for a bike with aftermarket/modified tailpipe/intake.

Cheers

[disenfranchised]

I can propose a slight variation on the exhaust mod.

Seeing as I already fitted a SD pipe to my bike, I have a spare stock one sitting around....and I suspect others out there may do too.
Find one, buy it cheap, and drill that instead, so you can go back to your original one if you have a problem (or to pass warrants)

[CookMySock]

I think the carbs are keihin? Not sure on that.

Just ask at any bike shop for jets. You can't really hurt anything by going up a size in jet.

Steve

[Slyer]

I think the carbs are keihin? Not sure on that.

Just ask at any bike shop for jets. You can't really hurt anything by going up a size in jet.

Steve
If the bike is already running rich and you go up a jet size you will be running even more rich...

[CookMySock]

If the bike is already running rich and you go up a jet size you will be running even more rich...I agree. But you can't HURT anything doing that.

[huff3r]

I agree. But you can't HURT anything doing that.

He's right, worst it'll do is slow you down a bit, whereas running lean can kill the whole thing!

[Sable]

Nice devaluing your bike there.

[wanpo]

Talked to the dude fixing up my bike, and he mentioned there's no oversized jets for Hyosungs as of yet.(I know there must be due to other threads.)

Anyone know where to pick up some in Auckland for a Hyosung GT250R? I'm thinking 97.5/100. (custom tailpipe and will desnorkle my airfilter)

[CookMySock]

Talked to the dude fixing up my bike, and he mentioned there's no oversized jets for Hyosungs as of yet.(I know there must be due to other threads.)Bogus. The carbs are twin Mikuni BDS26, so just wander into the parts department of any bike shop and ask for jets for that carb.

Steve

[wanpo]

Cheers, will do when I get my baby back.

It's humiliating riding around on the loan scooter >.>

[sapperj]

Well I have just purchased a cycleworks can and as someone put it "De-Snorkled" my air box, CDI mod allready done by previous owner. I went for a ride to my brothers place and checked the plugs there, all good on std carbies... I noticed much smoother accleration from 0 to 100 in all gears and a stronger top end. As a precaution I will adjust the needles and keep an eye on plugs etc.
Good to see some constructive comments here and I also find it quite entertaining to read the BS.

Keep ur knees in the breeze.
Jas

[CookMySock]

Well I have just purchased a cycleworks can and as someone put it "De-Snorkled" my air box, CDI mod allready done by previous owner. I went for a ride to my brothers place and checked the plugs there, all good on std carbies... I noticed much smoother accleration from 0 to 100 in all gears and a stronger top end. As a precaution I will adjust the needles and keep an eye on plugs etc.
Good to see some constructive comments here and I also find it quite entertaining to read the BS.The snorkle is part of the resonant intake plenum system, like the port on your subwoofer. Removing it will chop a hunk off the torque peak at around 5-7,000 rpm which is quite likely why you bike feels like it has more top end.

Just guessing.

Steve

[CookMySock]

Well I have just purchased a cycleworks can and as someone put it "De-Snorkled" my air box, CDI mod allready done by previous owner. I went for a ride to my brothers place and checked the plugs there, all good on std carbies... I noticed much smoother accleration from 0 to 100 in all gears and a stronger top end. As a precaution I will adjust the needles and keep an eye on plugs etc.
Good to see some constructive comments here and I also find it quite entertaining to read the BS.The snorkle is part of the resonant intake plenum system, like the port on your subwoofer. Removing it will chop a hunk off the torque peak at around 5-7,000 rpm which is quite likely why you bike feels like it has more top end.

Just guessing.

Steve

[sapperj]

[QUOTE=a) Modify the stock airfilter (cut the tiny circular hole so the size of the entire oval. Easy-peezee, you'll see what I mean when you take the tank off.
Will take about 30-45mins all up.] actual = 15 mins lol

:blink: So Im guessing the sub woofer thingey that was part of the stock air filter is what is being refered to here, so that is what I have done! Alas it is still the original paper element filter so I'm not expecting much in the way of increased air flow.

Have done the needles so tomorrow will be interesting to see if there is a noticable difference.

DB, I did notice that before I did any of the afore mentioned mods, the bike would feel 'retarded' or like it was maxed out at around 10K, now it pulls through 11 1/2 and dosent seem to mind (4th to 5th WOT) allthough I wont be pushing into the red normally, this time I was waiting for it to gag and was surprised to see it push through :shifty:

[CookMySock]

So Im guessing the sub woofer thingey that was part of the stock air filter is what is being refered to here, so that is what I have done! Alas it is still the original paper element filter so I'm not expecting much in the way of increased air flow.Yes. The air filter element on the 250 is fooken enormous. The same filter element is used on the 650 and that will flow 80hp+, so you should not think that hacking the filter element will do anything useful.



Have done the needles so tomorrow will be interesting to see if there is a noticable difference.That should give it a kick in the pants at partial throttle. You really need the main jets opened up a little to richen at full throttle.



DB, I did notice that before I did any of the afore mentioned mods, the bike would feel 'retarded' or like it was maxed out at around 10K, now it pulls through 11 1/2 and dosent seem to mind (4th to 5th WOT) allthough I wont be pushing into the red normally, this time I was waiting for it to gag and was surprised to see it push through :shifty:The seat-of-the-pants-dyno is only useful for drawing immediate comparisons, ie where the power band has moved to. If for example you chopped a hunk off your mid-rand torque, it will trick you into thinking you have just added more top-end power, certainly since you believed thats exactly what it would do.

The whole point of the resonant intake box, is mid-range torque, and you quite likely just chopped a hunk off of it with that mod. Certainly if it was your subwoofer and you removed the port tube, you would have crippled it.

Basically you aren't in a position to dyno it so you are stuck with your mind playing tricks on you.

Best mod should be, do the exhaust, raise needles, and go up a size or two on the main jets. I wouldn't futz with the airbox. It would be nice to fiddle with the ignition timing on a dyno, but thats not really feasible without $500 worth of ignition controller, and $twice that of dyno time.

Steve

[sapperj]

Cheers for that man,

As things are looking pretty dirty in there (air filter) I will be looking at replacing soon anyway.

Soooooo on the subject of filters, whats your take on the likes of K&N etc?

Jas

[Hiflyer]

Cheers for that man,

As things are looking pretty dirty in there (air filter) I will be looking at replacing soon anyway.

Soooooo on the subject of filters, whats your take on the likes of K&N etc?

Jas

As far as I'm aware only BMC make high flow airfilters for hyosungs and the distibutor in NZ doesn't bring them in anymore. That was a while ago, maybe like july last year? so it may have changed

[wanpo]

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.

[CookMySock]

Soooooo on the subject of filters, whats your take on the likes of K&N etc?As I was sayin, the standard GT250R air filter is also used on the GT650R, where it will happily flow 80hp+. So I'd suggest futzing with the air filter will spend your money no worries, but thats about all, and it will certainly not flow any more air no matter what you do to it, other than pump some air in. (maybe a project to be considered.)

I don't know whether the standard exhaust (other than the muffler) could be improved or not, but my guess is "not". 50mm exhaust is friggen huge for a 250. Vtwins sound awesome with a mildly noisy muffler on it, so that is required "tuning" anyway - gain in hp is irrelevant next to the gain in enjoyment riding it.

It would be nice to tune spark, but there's not really any plug-n-play way to do that, and then you need dyno time to use it, and for perhaps 2-8 hp gain?


Steve

[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!

<img src="http://www.motorcycle.com/gallery/gallery.php/d/219851-2/2009_Magro250_Comparo_Dyno_Charts_ALLTorque.jpg" width="600" height="500">


<img src="http://www.motorcycle.com/gallery/gallery.php/d/219855-2/2009_Magro250_Comparo_Dyno_Charts_ALLHP.jpg" width="600" height="500">

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 :bleh: 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. :niceone:

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 :innocent:

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..

[wanpo]

ok, I'll give 91 a shot, I generally try to run 98. I'm only filling up like $5 bucks at a time at the moment, cus I'm still trying to mod the air filter to fit over the top of the carbs and make it more weather friendly. (Lifting off a full tank every time isn't fun; that and I think my fuel cap isn't air/petrol tight)

[CookMySock]

Lifting off a full tank every time isn't fun; that and I think my fuel cap isn't air/petrol tightIt isn't supposed to be airtight - it has to allow the tank pressure to equalise or the engine will run lean and eventually cut out. There is actually a fuel cap mod to unsure this happens properly.

You do realise there's an automatic (engine vacuum operated) fuel tap on the tank? Just pull the hoses off the tank and let a few teaspoons of fuel run out, and then it stops flowing. Step away from the bike for 1-2 minutes while the fuel evaporates off the engine area. Consider having a fire bucket on hand at least.

Steve

[wanpo]

yeah I heard it had an automatic vacuum seal, but in practice.... had to plug up the fuel line with metal rod cus it didn't stop flowing and I couldn't turn the tank upside down, cus the fuel would come out of the cap, so now I'm just putting small amounts of fuel in until I no longer have to work on it.

[CookMySock]

There's something wrong with the vacuum tap then. Not that it will affect normal operation of your bike.

Steve

[sapperj]

Thanks to all the great advize from you all here, I have done the following.
1. Cycleworks performance muffler
2. Air box mod, became K&N filter
3. CDI Mod, allready done
4. Up 2 jet sizes (F=97.5 >R=100)

Special thanks to TrippleZee Cycles, Kaiweka Suzuki, Cycleworks and KiwiBiker Forums.

I had a few problems getting the correct jet numbers for ordering,
FYI: Carbs are 'BDS 26' Jets are Mi-N 102.604 / 100 where 100= Jet size

[CookMySock]

Nice! :niceone:

Now to mod those chickenstrips!

Steve

[Hiflyer]

Nice! :niceone:

Now to mod those chickenstrips!

Steve

Haha that should have been the first mod before any performance upgrades

[gatch]

Haha that should have been the first mod before any performance upgrades

Agreed. You can gain an extra 20 hp on a 250 by learning to ride it.

[sapperj]

Chicken strips???

So where do I learn to ride a 250 superbike lol... Looks good in my garage :P

[sapperj]

Right........... chickenstrips lol. So how far do you push 2 week old Shinko's?

[CookMySock]

how far do you push 2 week old Shinko's?Properly warmed up, on smooth dry surfaces - as far as you like.

Steve

[Hiflyer]

Properly warmed up, on smooth dry surfaces - as far as you like.

Steve

Or you could get some Battlax bt 45's theyre much better than shinkos,

although on my old bike, the shinkos had smaller chicken strips, but I could never seem to wear them off on the BT45's for some reason?

EDIT: Shinko's are fine don't get me wrong, but there are better tyres out there

[CookMySock]

I've seen heavily abused shinkos on a GT250R with no strips, ay weaver. :niceone:

Mind you, the bike had been through its' share of fences, and looked fairly abused as well, so ya roll ya dice and ya pays ya money!

Steve

[gatch]

The thing is with crap tyres, they wont give any sign you are close to the limit of grip, they will just let go..

[CookMySock]

The thing is with crap tyres, they wont give any sign you are close to the limit of grip, they will just let go..Nah the shinkos skitter around like you are on ice - they are fucking scary in the wet or the grit.

It's good training though, because you learn to relax and let the tires have their little tantrum - and lo and behold you are still upright!

Steve

[gatch]

Nah the shinkos skitter around like you are on ice - they are fucking scary in the wet or the grit.

It's good training though, because you learn to relax and let the tires have their little tantrum - and lo and behold you are still upright!

Steve

My vfr came with IRCs front and rear, I have never been so scared for my life in the wet..

[CookMySock]

My vfr came with IRCs front and rear, I have never been so scared for my life in the wet..Yeh but they don't ditch your arse - they just make it feel like they are going to ditch your arse.

This is not a bad thing! You get used to the sensation and don't panic. To make quality tyres talk to you like this takes either great levels of skill, or great levels of stupidity.

Steve

[sapperj]

After riding with the K & N airfilter I realised the Induction Roar was so Fkn loud that...
a. I couldnt hear / enjoy the exhaust note and
b. My teeth hurt from the noise

SO...

I was going to see if I could fit the airbox over the filter but while playing around I discovered that it fit snugly inside the oval of the airbox, so I made a plate up, screwed the K&N to it and dropped it in the hole like a std one would go...

NOW...

Off for a ride to try it out :yes:

[CookMySock]

I made a plate up, screwed the K&N to it and dropped it in the hole like a std one would go...But why? That same airbox and stock filter will flow 80hp on the 650. Whats the point?

Steve

[sapperj]

But why? That same airbox and stock filter will flow 80hp on the 650. Whats the point?

Steve

Because I allready had bought the K&N... and cut / modded the stock one as previously discussed. I figured I might as well use what I've got... If only I knew then what I know now...

And yeah, much nicer to ride... can hear the exhaust again :)

[yokel]

Hi there people, I've just got my self one of these Hyo gt250s and looking at doing the mods thing.
I guess the first thing is a new muffler witch is a given but would like to know if there is any performance gains in ditching the catalytic converter?
Any other usefull tips on mods would be great!

Chur
Scott

[sapperj]

I guess the first thing is a new muffler witch is a given but would like to know if there is any performance gains in ditching the catalytic converter?


Cat converter? where is that?

[yokel]

Well I'm assuming that were the header collector is is some kind of cat? but maybe its not?
anyways I need to run the thing in before I get too carried way!

[sapperj]

Yeah as far as I know it is just a collector, not a cat. I have been told by some people that there is major restriction in the exhaust pipe at the point where it enters the box, and looking at it I would agree, even the header pipe reduces prior to the box, which in my mind is backwards... but having spoken to Daemon @ Cycleworks in Lower Hutt, he advised me to leave it as is. Mainly because the cost of remaking the exhaust system would not justify the small gain in top end.
Put a 'nice' sounding muffler on it and just ride...

[CookMySock]

Daemon @ Cycleworks in Lower Hutt, he advised me to leave it as is. Mainly because the cost of remaking the exhaust system would not justify the small gain in top end. Put a 'nice' sounding muffler on it and just ride...The only exhaust mod that is worth while, is to split the collector box and remove the baffles, as they work loose and rattle like a stone in a tin can - ugh. You might get a little more exhaust snort from it doing this too. Yum.

You might also weld up the little gaps in the pipework so it doesn't "pffft" so much. I don't know if they are there for a purpose, but they make the bike sound like shit so I weld them up - a ten minute job with the MIG and a tin of black spraypaint.

Reassemble the exhaust verrry carefully so there are no leaks - this keeps the bike sounding extra phat and rorty. Put some coppercoat on all the nuts and bolts.

But yeah, a loud exhaust on these bikes is mandatory. If you haven't heard one, you owe it to yourself to check it out.

Steve

[gatch]

Yeh but they don't ditch your arse - they just make it feel like they are going to ditch your arse.

This is not a bad thing! You get used to the sensation and don't panic. To make quality tyres talk to you like this takes either great levels of skill, or great levels of stupidity.

Steve

What ? When the front locks up with only mild braking, tries to slide out from under you when turning and anything more than half throttle spins the rear ? They are shit tyres..


Put some coppercoat on all the nuts and bolts.

Nickel anti seize if you can for exhaust stuff, it retains its anti seize properties better through high temps..

[CookMySock]

What ? When the front locks up with only mild braking, tries to slide out from under you when turning and anything more than half throttle spins the rear ? They are shit tyres..Ok I stand corrected. :laugh:

Sounds like shinkos are not quite as bad as that.



Nickel anti seize if you can for exhaust stuff, it retains its anti seize properties better through high temps..Wft? Is this some modern shit? :laugh:

I still got my tub of coppercote from way back. ;)


Steve

[sapperj]

I have a mate here at the workshops, will look into the collector box thing... I dont have my own mig :(
Probally cheeper than remaking the whole thing too.

So Steve, why dont they just have a Y pipe where front and rear headers come togeather? what does the 'collector box' actually do?

BTW I still use copper coat too lol

[gatch]

Ok I stand corrected. :laugh:
Sounds like shinkos are not quite as bad as that.

Wft? Is this some modern shit? :laugh:
I still got my tub of coppercote from way back. ;)

Steve

Man those IRC's are just horrid in the wet, ok in the sun, but thats about it.. Give me cheng shin or kings any day..

Yeah nickel is good. We've had plastic forming dies come in where copper anti seize has been used. It has dried to the point where it comes out looking like loctite thread locker and has made getting studs out even harder..

Anyway sorry, back to the hyosungs...

[CookMySock]

I dont have my own mig..

why dont they just have a Y pipe where front and rear headers come togeather? what does the 'collector box' actually do?Theres lots of cheapo gasless MIGs on trademe. Good fun to play with!

There is lots and lots of collector-box theory and I haven't got into all that. Google is sure to give you hours of great reading on it.

A more-than-cursory look at the hyo collector to muffler pipe, reveals that it's a little special. Theres actually two pipes in one between the collector box and the muffler. Take the muffler off and have a look at the tailpipe. Does anyone know what's going on with it?

Steve

[sapperj]

Well those Shnkos provide some interesting moments, Riding to Palmy from welly this arvo, hit a few wet spots and while doing a passing move, hit some diagonal white lines in the other lane and got a grove on lol, I dunno if it is the Shitkos or if all tyres get loose at times.... but yeah the things have a tendancy to feel unstable at times, I am running the factory recomanded preasures but want to go up a pound or two just to see if it makes a differance. My guess is the koreans factor the average solo rider to weigh in around 65 >70 kg ( luv those asian ckicks too :p ) not fat kunts like me 105K lol

[CookMySock]

It's the shinkos. It takes either a lot of bravery or a lot of stupidity to provoke a quality tyre such as Michelin Pilots into doing that.

It was such a fucking relief getting onto quality tyres, and took me months to just GO and trust them, especially in the wet.

Steve

[Eyegasm]

Well after 12000k the Shitkos have finally got to be replaced.
Bike was just serviced and the Rear tyre is below the legal limit.

Can not get the Pilot Road 2's and am going to try out the Perilli Sport Demons.

Any of you ridden these tyres before?

[CookMySock]

Pretty sure the 250 rims are the same as the 650 rims, and you can get michelins for the 650.

But the pirellis should be fine.

Steve

[CookMySock]

The 650 rear wheel is different to the 250 rear.

Both the 250 and 650 front rims are 96.5mm across the widest part.

The 250 rear rim is 121.5mm, and the 650 rim is 135mm.

I know the 650 front rim will fit perfectly on the 250, coz I tried it. I haven't tried the 650 rear rim on the 250, but I can't imagine it will be much work to make it fit. The sprocket will need changing. I don't know if the sprockets are a straight swap.

But if anyone is bold enough to try it, perhaps all you need is a new 650 rim, and then you have a much better range of tyres to choose from.

Steve

[vindy500]

The BT45 on mine seems alright

[gatch]

Well after 12000k the Shitkos have finally got to be replaced.
Bike was just serviced and the Rear tyre is below the legal limit.

Can not get the Pilot Road 2's and am going to try out the Perilli Sport Demons.

Any of you ridden these tyres before?

Sport demons will outperform you hands down on the road, if you are riding at a competitive pace on the track they will wear pretty quick. But you need to be really boogying..

[McWild]

I had Pirelli Sport Demons on a CBR250 I took from Christchurch to Whakatane.

Not once did I lose faith in them, and they were getting worked fairly hard on some of the sections of road.

Do it.