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Author Topic: 2012 GT250 Lurching at Low RPM  (Read 355 times)

zundapp

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2012 GT250 Lurching at Low RPM
« on: March 14, 2017, 07:27:44 PM »

Greetings from Florida

My 2012 GT250 w/2000 miles lurches when going from on throttle to off throttle and back to on throttle when engine is turning less than 6000 rpm.  The lurching makes the bike awkward to ride when in slow moving traffic, crowded parking lots, etc.  Must constantly use clutch to counteract the lurches.  Even using small changes in throttle position brings about a lurch.  Bike also has flat throttle response below 5000 rpm.  I mention this in case it is associated with the lurching but I do not view it as a problem.  Bike starts & idles well and performs flawlessly above 5000 rpm. Its a joy to ride when in the Dr Jekyll mode but Mr Hyde is hard to accept.

There is no proper Hyosung dealer in my area so the repair will be a DIY project.  I could really use some ideas as to where to start.  Any suggestions would be greatly appreciated.
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Hylife

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Re: 2012 GT250 Lurching at Low RPM
« Reply #1 on: March 22, 2017, 08:09:39 AM »

Download all the manuals for your model bike from here and then adjust the throttle cable for less slack.
http://www.hyosung.hu/download/pdf/letoltesek.htm
http://www.hyosung.com.au/about-hyosung/owners-manual/

The TPS may also need adjustment but it is a real bitch to get right as when you tighten the bolt the setting can change. You will require a digital multimeter to adjust the TPS and it WILL take multiple attempts to adjust correctly.
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2011 GV250 - 2011 GV650C - It's not 'what' you ride, it's 'that' you ride.

zundapp

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Re: 2012 GT250 Lurching at Low RPM
« Reply #2 on: March 22, 2017, 07:45:16 PM »

Many thanks for the tips.
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zundapp

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Re: 2012 GT250 Lurching at Low RPM
« Reply #3 on: March 25, 2017, 01:25:43 PM »

Many, many thanks to Hylife for responding to my issue and recommending throttle cable adjustment.  After removing as much slack as possible from the main cable I checked the functioning of the throtle bodies.  They were not moving in unison and one was not reaching maximum travel.  With some minor tweeking of the cable adjusters (NOT THE STOP SCREWS) on the throttle bodies I achieved uniform movement.  Took the bike out for a test and discovered lurching problem is completely gone.  I'm now very happy thanks to Hylife.  Life is good.
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