Re: Throttle is heavy
might be something as simple as the bar end has got knocked and tightened up the throttle, failing that take the throttle grip apart and oil the cables. and leave them overnight.
If neither work then new cable is an easy thing to sort out, but if its still rideable I would wait until next service, that way you can take the bike apart and do it the same time you check the valves and carbs etc..
1986 Honda NS400R - Almost new
1988 GSXR750 Slingshot - Very mint
1989 RD03 XRV650 - Even minter than above