17th Mar 2009, 20:42
I have a GT 650 Comet, and it runs perfectly as long as you follow the break in and fuel procedures. Nowadays they're beginning to add ethanol to gas, and if the octane rating drops below 90, most Hyosung bikes with a 250 engine or higher are rather intolerant. The problem is that the petcock is not designed for ethanol fuel, and if you go through a tank or two of gas with too low an octane rating, you'll end up having to replace the entire petcock.
In addition, Hyosungs are particularly needy in terms of adherence to the break in procedure. For the first 500 miles (800km) try to stay below 4000rpm and 1/2 the throttle. After that, keep it below 6000rpm and 3/4 of the throttle until 1000 miles (1600km).
Also, keep an eye on the oil. The manual says to replace oil and filter after the first 500 miles, but the 650 models burn oil fast during the break in, so I changed mine out at 300 miles, and sure enough the oil and the filter were black and the magnetic tip, of the oil drain screw, was covered with filings. After I changed it at 700 miles, the oil was noticeably cleaner and the filter was not nearly as dirty, but I still changed it for good measure.
Overall, there is nothing really wrong with the GT 650's other than a less than accurate assumption of break in procedure. If they'd change the manual, most of these problems would probably be avoided. Just take care of your bike and it'll certainly take care of you.
30th Jan 2010, 23:14
I just bought 2007 GT-650R; the one with flames. I love this bike, just one problem with it; the battery it will not stay charged. Yes I bought a new battery, still the same thing. Need help...
17th Feb 2010, 03:29
Owned: Hyosung 650 Comet? 07.
"?" meaning which model when going to buy rear brake pads... minor problem. Much like the brakes shredding within the week... so don't bother :)
General parts... I had my starter button "modified" by a well intentioned gentleman... a new throttle grip assembly is actually cheaper than the air filter? ummm?
Was restricted when purchased, clocked up 5000km... 3000 miles? Then changed slides, sweet...
Redline constantly, barely service, 5000km oil changes, when I have the money, like every other repair.
Sidestand switch! Would run happily in neutral at the lights, stop when you pop in gear.
cut the wire, beautiful (make sure you don't cut the neutral wire instead... that one's blue :) )
Battery lasted almost 2 years... just started dying recently, regulator fried. Replacement from who knows what fried as well. So original battery's still fairly good... :)
New regulator time... and all the other junk if needed... fingers crossed.
Recent tendency to wobble some... hard to hold straight lines and loves left handers... is not the wheels out of line. Also intermittent... head bearings. All bearings probably by now...
Total of 56000+ km, still runs hard. 2 chains, 5th set of tyres...
19th Jun 2011, 23:31
This is why I do all the work on my motorcycles myself, and when the dealer offers 500.00 Triumph gear or whatnot, I request the dealer service manual and tools. I bought my Triumph new, and now have 30,000 miles on it. I have done all work myself. My feeling is that if you can't do the maintenance on your vehicles yourself, then you shouldn't own one. Go ride the bus.
25th Sep 2011, 07:47
I love my GT650s, but the big problem I'm running into is finding an oil filter from auto zone etc. Any help would be great! I don't know the size it takes either.
14th Feb 2012, 20:04
I concur. My 07 Hyosung only has 1800 miles on it, and the engine has to be replaced. Oil leaking from the middle of the motor, and the Hyo guy couldn't explain it. I don't stunt or ride hard, so can someone explain that?
14th Feb 2013, 00:58
That's right, they bagged Hyundai, but now look at them. Give it time and they will be as good as any of the other sports bikes on the market... I have a 2008 model, and it goes as good as any v-twin I've ridden after a little tweaking.
30th Aug 2013, 14:39
I also own a Hyosung 650 Comet, which is a 2007 model, and it has 13000 km and has an oil leak on the centre of the bottom of the engine. How can I solve this problem?
14th Sep 2013, 21:42
Hello Hyosung fans. I own a 2008 GT650R and have had no issues. I love this bike, it performs great. I am waiting on the 1000, 1300, or 1400 to come out someday. Japanese bikes stand by, because the race is on! Norfolk Va.
20th Oct 2015, 15:35
So I just bought a 2008 Hyo Comet 650 with 2600 miles...
The guy didn't take care of it really, bone dry fluids and a missing air cleaner altogether. Secondary air cleaner hoses have been cut. I'm thinking of just putting on cone filters to the carbs instead of buying a factory air cleaner?
The bigger problem is the transmission; there's no second gear. I basically have two neutrals; I can shift into second, but the gears don't catch. I can shift all the way up to fourth, but can't shift into 5th; it's as if I'm topped out at 4th, but I know the bike to have 5 gears.
I plan on doing a full engine rebuild (replacement of seals, o-rings, circlips... hopefully not the bearings) to get down to the trans. I believe the shifter forks are the problem with second gear, however I'm unsure as to why I cannot grab 5th.
After topping off all the fluids, the bike starts up first shot every time and this thing is FAST. Any advice on the transmission/air cleaner would be appreciated.
9th Jul 2017, 17:53
I need help with my 2008 Hyosung GT650R. Where can I order a new petcock and get it reasonably fast, and/or are there parts off another brand bike that may fit?