I've researched every related top regarding this, however I've never come across some solid information to fix this problem, or found a definite answer - however I was advised that korider is the place to be.
It seems to be a "similar" issue occurring on Hyosung bikes. My Bike is a 2014 (non-digital-dash) model of the GT 125 Comet, the body is immaculate and has done less than 3000 miles.
The bike starts perfectly, it does idol. I haven't ridden it much to test power/speeds etc etc.
The main thing bugging me is - when the bike is in idol, itermittently the engine (seems to be on the West of the engine, towards the top of a cylinder (not sure which) or -the carbs, seperate from the natural sound of the engine is a cranking / grinding / scraping noise, it's noticable but doesn't quote overwhelm the natural sound of the bike, it happens very intermittently, twice in 20 seconds, once every 4 minutes, 3 times in 136 seconds.... lasts for around 5 - 10 seconds, so it's not constant.
My other concern is the bike starts fine (GT 125's in general do tend to need a good warming up to tick-over smoothly) it starts, idols, warms up and never stalls. however when it's idoling if I pull the choke slowly to around half way it revs up to 6000 7000 RPM, if I pull it all the way down the bike cuts out.
Definitive advice on this would be massively appreciated.