So for a while now my 2006 GT650R (20,000kms) has been acting up. For the most part it runs like a dream idles fine and runs great. However occasionally and more recently than ever it starts to jerk/lug and seems the pistons are firing irregularly. It can be extremely dangerous especially on a slow corner when the power lacks and picks up and lacks again kinda throwing you all over the place. The only quick fix I have is throttling up with the clutch in when I'm forced to go slow (traffic/corners). I feel like an a**hole doing that and obviously this is a sign there's something severely wrong in which I would not like to continue to cause harm.
Only happens once the bike has warmed up to normal operating temperature and then after highway riding (roughly say 10 min at 120km/h 7-8,000 RPM) then entering back roads for 10 min or slow moving traffic where I'm forced to go into 1st or 2nd gear with low RPM. Most times I've noticed it happen I was doing 30km/h in 1st gear around 3-4500 RPM. Recently it has also started in 2nd gear around 55km/h at around the same RPM.
Usually I can rev the RPM higher or lower gear to increase RPM and the problem vanishes (goes back into hiding). Lately if I increase the throttle a bit when its lugging it doesn't accelerate like it used to, kind of bogs a bit. So I have to really throttle it. At highway speeds and the back roads on the way to the highway in the morning it's fine. In fact it was fine for 3 days and then it started again and then it can be another couple days before it happens again. The temperatures seem normal, rarely goes into red and when it does the fan kicks it down again.
I have pulled the spark plugs and looked at them, they are covered in a light grey dust and seems right. I also pulled both carbs off and did a thorough cleaning finding little small particle debris in the floats. Ran great for a week until here the problem arises again. I also recently took my bike to the only dealer within 300km that will touch a Hyosung. The owner of the small shop who supposedly specialise in Hyosung and scooters told me he couldn't see any problems after a servicing. I had him ride the bike too and do a tune up just in case something pops up but the results were clean. He believed that my bike in particular was that of one of his apprentices from a while back who constantly kept it serviced before selling it to whom I purchased it from. It was in rough shape when I got it. Dead battery, faulty spark plugs, no front turn signals (cut actually), bad oil, little no coolant and brake pads down to the metal. I was angry as it's my first bike and he told me it was good to go for the season and ripped me off.
If you guys can help me out and or offer any suggestions on what it could be as well as ask any questions that hopefully I can answer so I can get one of the final problems with this bike figured out I would GREATLY appreciate!