Greyhogs

Hi mate, checkout the post called Hyosuck posted by KIPS powerband. He was having similar issues and got some relief. I can't remember how to quote one thread into another but it is easy to find

I asked the guys at hyosung if they knew anything about the "retard wire" in the cdi, others have taken out the brown wire and had success. However not sure what your meaning about it cutting out?
Hyosung told me "sure go cut the wire then come back and buy a new cdi unit" they suggested having the machanics look at it at $80 an hour until they find it.
Now I only asked about it didn't say i was going to try anything and he almost busted a nut over my query.
Chances are if I tried anything i'd somehow manage to blow up my suburb

had one bike doing this when i was working on hyosung it proved to be a bad connection in the cdi, was bloddy hard to trace as it would never fault when the customer bought it to us. This bike needed to have been running for 10 15 min and then hit a bump to bring on the fault, is this what yours bike is doing? Do you know any one with the same model of bike that you can give your cdi to to test to see if the fault swaps to there bike with your cdi fitted.

Vacume fuel taps had a known fault, and were changed out on alot of GT's under warranty.
Basically, they struggled to supply enough fuel to the carbs over about 15kms, until the fuel level lowered too far, and the bike would stop.
By the time you tried to restart a few times,the fuel level lifted enough, so the bike would retart.
Inaccurate machining of the clearances inside the fuel vacume tapassembly was the fault.Out by about 005".

Frustrating and time expensive to fault find.
Maybe try a manual,(non vacume)tapfrom the wreckers off a similar sized bike.
MHO

PS, Scottyand the team at Hyo NZ are good blokes.