see, kbatl clutches dont do toad unless they're fettled
zx4 engines fly mate .. my first zx4 was internally stock, the link pipe was crudely de-baffled and it had a home made air filter (cos you couldnt get import spares in 1997) and thames valley police gave me 5 points for doing 143mph on it .. took em 7 miles to catch me n all
our current one murdered my L for topend, and it was completely standard at the time except for an L exhaust (with standard quiet road can), while the L had a full micron, DJ kit, KnN..
rumour has it they have essentially SP cams

but i've never had one apart at the same time as having anything else to compare them to..
superbike mag tested one in a "budget 400" group test years ago against an early gsxr, cb-1, and an early fzr and it gave close to 60bhp completely stock and not setup.
you dont "set" the tensioner as such, winding it in releases the ratchet mechanism so it'll slide up n down freely, then the spring does the tensioning and you back it off till the groove lines up and you can put the circlip back on... if it aint rattling i'd leave it alone.