**HELP** rejetting carbs

[Qu1ckset]

So i was planning on rejetting my carbs and i heard it was easy... I dont feel like paying a arm and leg to get it done at a shop... I was curious if any1 wud be able to do it for me..

[Sushii]

http://www.ehow.com/how_2123411_reje...otorcycle.html

[inreb]

So i was planning on rejetting my carbs and i heard it was easy... I dont feel like paying a arm and leg to get it done at a shop... I was curious if any1 wud be able to do it for me..

OK, I'll go ahead and guess that it's a 1979 six cylinder Honda CBX with custom strocker crank and other exotic "one off" speed parts. There will be no known baseline, so you'll have to start from scratch. Who said it was easy?

[Qu1ckset]

lol sry the bike is a 2009 hyosung gt250r

[bobjohnson]

Why do you want to rejet? Unless youve done some modifications, the stock jetting is fine.

[Hachi-Roku]

lol sry the bike is a 2009 hyosung gt250r

You're re jetting a 2009 hyosung gt250r?

Why?
Or better question would be How?
Since the 2009 GT R's are EFI

[andrei14]

So i was planning on rejetting my carbs and i heard it was easy... I dont feel like paying a arm and leg to get it done at a shop... I was curious if any1 wud be able to do it for me..

this sounds like a "if it ain't broken... break it" kinda project.
do you have the stock can and filter on it? if yes, you're already finished...

[silent_vik]

You're re jetting a 2009 hyosung gt250r?

Why?
Or better question would be How?
Since the 2009 GT R's are EFI

its carb'd. 08 and 10 are EFi. i know. weird.

OP is getting a new bolt on exhaust. while its not super necessary to rejet on this bike with just an exhaust, but it is for sure a good thing if u dont want the popping on decelerating and to get the right fuel mixture. get a high flow BMC air filter and iridium spark plugs while u r at it and then rejet.
i have no experience on a carb'd bike, but this might help you.
http://korider.com/index.php?topic=381.0

[inreb]

this sounds like a "if it ain't broken... break it" kinda project.
do you have the stock can and filter on it? if yes, you're already finished...

sometimes it's beneficial to take the lean out of the idle and/or pilot circuit, they tend to come lean from the factory

[Hachi-Roku]

its carb'd. 08 and 10 are EFi. i know. weird.

OP is getting a new bolt on exhaust. while its not super necessary to rejet on this bike with just an exhaust, but it is for sure a good thing if u dont want the popping on decelerating and to get the right fuel mixture. get a high flow BMC air filter and iridium spark plugs while u r at it and then rejet.
i have no experience on a carb'd bike, but this might help you.
http://korider.com/index.php?topic=381.0

Looks like the 09 came in both
http://www.bikez.com/motorcycles/hyo...r_efi_2009.php

that odd. Maybe left over 08's

[silent_vik]

yea. thats the thing about Hyosung. every country has a little bit of different models for the same year. they introduced fi in canada in 2008 but 2009 went back to carbd because too many of the carbd engines were left over. now back to fi for 2010. thats why the 09s are going about 2k cheaper than their original price which should have been the price for these bikes to begin with.

[andrei14]

sometimes it's beneficial to take the lean out of the idle and/or pilot circuit, they tend to come lean from the factory

very true... then again... it doesn't matter that much at low revs... rejetting can be a nightmare if you don't know what you're doing... so I wouldn't bother with it.

[Red_Liner740]

its a lot of work to rip into the bike to fix a problem that is not there.

your popping on decel is most likely PAIR, not sure if the bike comes with it but alot of bikes do for emmission purposes....it dumps fresh air into the exhaust to try and burn up any unused fuel....hence the popping on decel.

[Qu1ckset]

i was planning on rejetting because i was getting a bolt on pipe on friday and possibly a bmc air filter... Maybe il jus get a shop to do it wen im ready...

[dirtbag]

isn't the real question: Why put a pipe and filter on a 250 Hyosung? Even if you got a 10% increase in power (which I doubt greatly) would you hardly notice it?

Sometimes your better off to jack up the gas cap and fit a bigger bike underneath it.

But if your keen to move forward and learn something new I say good on you. Have you done some plug chops to figure out where the baseline is?

[Qu1ckset]

im prolly only gunna end up putting the pipe on not the filter... I am not putting the pipe on for performance gain its a 250 lol im doing it more for looks and sound.. you cant even hear the stock pipe wen reving all you here is engine.. I was planning on re jetting the carbs cuz i heard its not good wen you dont, and the btw i find the hyosungs run really rich, which is gunna prolly cuz alot of backfire.. Cuz i here my stock pipe do it sometimess lol

[cars n' women]

So i was planning on rejetting my carbs and i heard it was easy... I dont feel like paying a arm and leg to get it done at a shop... I was curious if any1 wud be able to do it for me..

if they are vacuum slide carbs you could use factory pro's tuning guide. pretty straight forward, all you need is your way around your carb and an arse dyno that can feel when you change a setting.

http://www.factorypro.com/tech/carbtun.html

click on either high or low rpm engine

remember that on 4 cyl bikes every carb may not have the same main jet/needle/fuel screw adjustment, sopay attention.

When you're done, synchronize the carbs

[cars n' women]

isn't the real question: Why put a pipe and filter on a 250 Hyosung? Even if you got a 10% increase in power (which I doubt greatly) would you hardly notice it?

Sometimes your better off to jack up the gas cap and fit a bigger bike underneath it.

But if your keen to move forward and learn something new I say good on you. Have you done some plug chops to figure out where the baseline is?

well when buying exhaust on bikes 600cc or less your not getting much power anyway, most bikes are well tuned from the factory with some restrictions for noise and emissions. its mostly for your riding entertainment... why would you want a bike that sounds like a vacuum when you can have one that sounds like a lil monster?

[imkruzen]

im prolly only gunna end up putting the pipe on not the filter... I am not putting the pipe on for performance gain its a 250 lol im doing it more for looks and sound.. you cant even hear the stock pipe wen reving all you here is engine.. I was planning on re jetting the carbs cuz i heard its not good wen you dont, and the btw i find the hyosungs run really rich, which is gunna prolly cuz alot of backfire.. Cuz i here my stock pipe do it sometimess lol

When you change the exhaust on any motor to flow free, you have better cylinder scavenging. This will be apparent when you look at the spark plugs after riding for a while. If the plugs are white you're lean. If you're indicating that your bike is already running rich, then just put the exhaust on and monitor the plugs. If you are getting a lot of backfire when you let off the throttle, you're too lean, not rich. If your carbs have needles, you might cure the lean condition, if that is the case, by raising the needle one notch by moving the circlip. I had done this on the Mikuni BS36 carbs on my bike to eliminate a flat spot below 3000rpm. When I put the header on it didn't require any other changes. Changing the air filter for a free breather will also tend to lean out the engine. DON'T USE K&N, they only stop boulders from getting into the engine. When you ride normally you never have restriction by the air filter. At WOT you might get a little bit of restriction, but not enough to notice. You would need a dyno to see.

Iridium plugs don't do anything for performance PERIOD! If your plugs are hard to get at, then you could spring for them or Platinum. If not use any copper core plug. The only plug that has confirmed improvements is the E3 spark plugs. For the miniscule improvement I won't be spending $17 on a plug anytime soon. Don't go changing things based on assumptions or here say.