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]

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...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]

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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]

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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]

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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]

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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]

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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]

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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:Me]

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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]

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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:Me]

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. Want more horsepower... BUY A BIGGER/BETTER bike.
Increasing horsepower shortens the "lifespan" with rebuild costs more than its worth.

Point one--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]

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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 .

Oh, and let me know when you grow up too

[NOMIS]

Reeeeeooowww