• Topics: 38
  • Replies: 485
Nov 30, 2017
North UK

For the coils,

1. Grab a multi meter
2. Red wire on the HT LEAD
3. Black wire on the spade-terminal of the coil.

You must get 5.0K – 6.2K Ohms maximum. That’s a healthy coil, any values beyond that, the coil needs replacing as they can’t be repaired.

5K = 5,000 ohms.

Like my example here..
(Black wire from your meter must test both the “terminal” spade and “fins” (where bolt slots through)
ignition coil hyosung gv250 gt125r


Take out your spark plugs , this image below was my laser iridium plugs after 2 years (20k miles) .
COFFEE BROWN =  Healthy fuel system including your carbs (optimal)
BLACK CHARCOAL = too rich or carb issues inside (gunk?)
BLACK & WET =  fuel smell = coils are not working or plug itself is shot.
BLACK & OILY = piston rings (God forbid!)
WHITE CENTER  = too lean… that will kill piston rings very soon! (Suspects = carbs , coils & plugs)

In all cases the last 2 are critical and no one want’s to be there… better to be richer than leaner…
ngk laser iridium plugs hyosung cr8e ix



You said you only had it 18 months. How many miles is it done so far ? & does it have history of service inspections  concerning the check for plugs ,  air filter clogged , and possible check on coils ?  if it was behaving erratic in the past before ?

If it was a new bike, the dealer would “have” to fix back to standard again as part of the warranty.


Pilots & Starting Jets  (2 other tubes next to main jet) control starting & idling , slow running until main jet takes over from 2nd gear ish or full open throttle.

Get a CLEAR hole , while cleaning , like my example below:
Pilots are VERY notoriously easy to gum up! –

A big fuel filter helps a lot prevent gunk going to the carbs in the 1st place.

A clean air filter is also important! – Some clogged particles do get sucked in!
hyosung pilot jets gt125r


“STARTER JET” is the jet that can’t be removed, but compressed air with a straw can blow hard through it or a carb cleaner is best.  The hole is much more tiny than the pilot!

// Meditation doesn't mean you have to sit still....

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