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Author Topic: GT250R Optimization/increasing power  (Read 361 times)

notjondo

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GT250R Optimization/increasing power
« on: December 04, 2018, 11:32:17 PM »

Hello! I'm planning on buying a 2009 GT250R and would like to have a few things cleared up.

Does the CDI mod work? I've looked through the thread and it seems that there is not really a clear conclusion.

What exactly is de-baffling the muffler? Will this be a replacement for getting a new exhaust?

I also know that desnorkeling and rejetting go hand in hand. I have read Mike's thread on this and am thinking about having 100/100 main jets with a single shim after desnorkeling. Is this a reasonable set up?

The rejetting/desnorkeling part might not even be relevant because apparently some 2009 GT250R
s are fuel injected but I'm not sure if the one I'm buying is.

EDIT: Also, I found this 6sigma kit: https://www.ebay.com/itm/Hyosung-GT250R-GT250-GT-250-Comet-Performance-Kit-Front-Sprocket-AIS-Jet-Kit/252660507999?epid=1655348119&hash=item3ad3bd655f:g:tg8AAOxyRNJSeWb5:rk:32:pf:0&LH_BIN=1

Is it any good?

I am sorry for breached rules. I am completely new to motorcycles so anything is helpful. Thank you!
« Last Edit: December 05, 2018, 01:02:31 AM by notjondo »
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2turbos

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Re: GT250R Optimization/increasing power
« Reply #1 on: December 05, 2018, 03:09:06 PM »

At least for now, unless there is a problem with the stock setup or reliability issues, my advice is to not mod the bike until you get some riding experience. You don't want to have to deal with both simultaneously. Relax, ride lots of miles and have fun. It will become apparent what you need to change the more you ride. Be safe!
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notjondo

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Re: GT250R Optimization/increasing power
« Reply #2 on: December 06, 2018, 10:24:18 AM »

Probably good advice for your average rider. However, I love to tinker and half of the reason I want a motorcycle right now is purely to tinker lol (it would also be very useful as a personal commute vehicle) so I kind of want to mod this thing right away. It's not really for the riding experience but more for the tinker/learning experience so any input would be great!
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umop-ǝpisdn

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Re: GT250R Optimization/increasing power
« Reply #3 on: December 07, 2018, 10:20:14 PM »

I 100% understand the NEED to tinker, but with that said, I strongly suggest that you do things in something like this order, so that you know you're not pissing your money away.

Start with basic maintenance: know that the bike is serviceable before you invest money in it
Oil, filters & brake fluid. Bleed the brakes as well.
Learn how to lube and adjust the chain and how to lube and adjust the throttle cables.

Make the bike reliable:
Electrics are the Achilles heel of these bikes. Consider investing in an upgraded charging system. MOSFET regulator/rectifier and add a sister wiring upgrade between the reg/rec and the battery to supplement the inadequate stock wires.

Make the bike more rideable: this ensures you are starting with a bike you can actually ride for a decent distance.
Clean the insides of the projector lenses to make them brighter.
Re-jet/rebuild the carbs
Rebuild the vacuum petcock and fuel pump.

Proper mods:
You can throw some timing at it.
http://www.ebay.com.au/itm/SCOOTER-125CC-150CC-GY6-CRANKSHAFT-Flywheel-RACING-DEGREE-Woodruff-Key/173675460667?hash=item286fdd383b:g:k~wAAOSw1UdbhY7b:rk:9:pf:0

A free flowing exhaust and a good air filter. These will require re-jetting your carb +25 for each airflow mod you make.

-1/+2 front/rear sprockets for lower top speed but higher acceleration.

That's about all you can do without spending big $s.
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I used to be a sensitive, new age guy, but times have changed and now I am more of a caring, understanding, ninties type.

notjondo

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Re: GT250R Optimization/increasing power
« Reply #4 on: December 08, 2018, 10:28:22 AM »

Alright! I'll look into it! A few questions for you:

Would you recommend a smaller front sprocket or a bigger rear? Reducing the front is cheaper but I heard it eats the chain. However, replacing the rear would mean I would need a new chain to accommodate for the larger size.

Also, any exhausts to recommend? Or would debaffling do the trick and save me some money?

Also can you link any good resources you might know of when it comes to rebuilding the carbs, vacuum petcock, and fuel pump
« Last Edit: December 08, 2018, 10:30:09 AM by notjondo »
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umop-ǝpisdn

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Re: GT250R Optimization/increasing power
« Reply #5 on: December 08, 2018, 08:29:02 PM »

For rebuilding the carbs:

http://korider.com/index.php?topic=381.0

As for the petcock and pump, they're pretty straight-forward. Undo some screws, then swap the rubber bits for new ones.
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I used to be a sensitive, new age guy, but times have changed and now I am more of a caring, understanding, ninties type.

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