Are the tappets manually or hydraulically adjusted ?
The 'valve clearance' is set by various sized 'tappet blocks'. Measure the clearance, compare what it should be,(Clearance, when the engine cold: Intake : 0.125 - 0.25 mm (0.0049 - 0.0098 in) Exhaust : 0.325 - 0.45 mm (0.0128 - 0.0177 in).) and select a suitably sized one.!!Are the tappets manually or hydraulically adjusted ?
I called them 'blocks' but in fact there are 25 different height size 'inverted buckets' no shims involved. !!...hmmm: tappet blocks sound a bit like the 'bucket & shim' setup on some older Japanese motorcycles...
...nice to know - even tho' I doubt I'll ever go anywhere near them!