Welcome to the forum!
any problems you have should get cleared up here.
mine done the same for a while, and still does it now.
ok here goes, a pretty rough explination of some things which can cure your problem!
there are many areas to check for 'sticking' in certain places throughout the throttle cable and grip assembly. first of all you should check that your cables (acceleration and deceleration) are both routed properly on the left side of the bike (left being if your in riding position) they should have no sharp kinKs or be twisted in anyway. next check the throttle grip, it should move freely and should be well lubricated to aid in it 'snapping' back to its orginal position.
Next bits the hardest part and requires some panels off....
take off the seat unit, fuel tank (disconnecting all cables and marking which goes where, TURN FUEL TAP OFF, and be very careful undoing the vacuum hose, which is a small thin tube connected to the back of the fuel tap on the tank, ideally disconnect at the metal connector to avoid it snapping or breaking.)
now if you remove some left hand panels, the top one is easy and should do, just to get some light in. Look down the left side of the carbs, you should see where your throttle cables route to on the carbs and where they connect. (if you cannot see much also remove the air box and its filter, again careful with the screws!)
they should all route easily and be smooth throughout the action. If there not then this is a last place to check, disconnect the cable housing from you're throttle on the handle bars, making sure its just the black housing which surrounds the handlebar which comes off, leaving the cables in the assembly. try putting some light viscousity oil down such as wd40 or 3in1 oil and wait for it to appear on the fixing at the carbs, as gravity will pull the lube down to there exit on the carbs, next try putting the throttle assembly back together at the handlebars and moiving the throttle back and forward as if you were accelerating and decelerating. this might free them up.
end of the day it works off the carbs which have preloaded springs to open them for fueling. these when open (accelerating) put the springs under more load meaning the throttle should 'snap' back to closed, but if they cant id suggest replacing the cables or adjusting then via where there connected on the carbs.
if you have a haynes it tells you about adjusting in there. if you havent got one let me know and ill supply more info for you from mine.
hoope this helps in the mean time.
regards.
Dan
worth a look.
