the not revving over 7k, in fact everything you describe, suggests the cam timing has been set up wrong - 180 degrees out.
you need to read and understand the procedure for replacing the cct as described in the guide in the workshop section.
you are like the 5th person this month so far who has had the exact same problem.
it's quite easy to fix.
you will need to remove the tank & airbox.
take off BOTH cam covers (makes it easier to be 100% sure the cams are set right.)
remove the inspection plugs from the timing cover on the left.
remove the spark plugs.
turn the engine over by hand, anticlockwise until the ft mark is in the timing window, aligned with the mark.
feel for compression by putting your finger over the plug hole.
check the position of the front cams - the FE & FI marks should be far left, far right, (not together in the middle & upside down) and the cam lobes facing away from each other, pointing diagonally outwards - this means the engine is on the compression stroke.
if it's not on the compression stroke, rotate anticlockwise 360 degrees and line it all up again.
thats the front set up ok, as reference. now check the rear cams.
turn the engine again 270 degrees or 3/4 turn to line up the rt mark.
the RI & RE marks should be right way up at the far left and right, as before, with the cam lobes pointing diagonally inwards .
(but they won't be - cos it's been set up wrong)
at this point, without moving the flywheel, remove the rear camchain tensioner (catch the bit of oil on a rag)
stuff bogroll down the camchain tunnel and remove the top guide
remove the cam cover from the inlet cam (the left one!)
remove the inlet cam.
jog the chain over the exhaust cam until the RE mark lines up with the face of the cylinder head.
refit the inlet cam so the RI mark lines up with the cyl head face.
pull the chain to the rear of the bike to check cam position under tension... the slack should be on the cct side.
adjust the cam positions if necessary by jogging the chain over the tops of the gears.
refit the cam cover and guide (use locking compound)
refit the cct and turn the engine over by hand a few times to check.
double check the cam positions before refitting.
line up the front again as above, then turn 270 and recheck the rear... if you are 100% happy then all should be ok so put it all back together and enjoy the vtr as it should be.

if you are taking it to someone to have this done, make sure they read & understand this - AND the replacing cct guide in the workshop section.
you do not have piston slap, the cam timing is wrong.
this should take a max of 3-4hrs for a nooby to do and 2hrs for a pro.
* the rough idle is also because of this, but once its back together you might want to check the carb balance.
if so it may be worth installing a front vacuum take-off point while you have it in bits.
this goes on the blanking plug on the front cylinder inlet under the carb.
break up a pushbike pump adapter for the brass adapter screw and fit a length of pipe to it (from any car accessory shop)
when not in use this can be blanked off with a golf tee or run to a scottoiler.
instructions for balancing are in the pdf manual, downloadable for free from the workshop link.
you can get a good set of vacuum gauges off ebay for about 20 notes.