Valve clearance settings
 

Just a quick question regarding the valve clearance settings. is it better to adjust the valve clearance to the tighter side or the loose side of the specification range?

You'll get many different views and opinions on this on this one I'm sure!

For me personally, I always set them at the looser end of the range. Why? Because valves clearances close up over time and a tight valve is much more damaging than a loose one, so I like to give a little room for this. Plus, with screw and lock nut adjusters, I always find that no matter how hard you try to hold the screw while you tighten the lock nut, it'll always nip up a fraction further than you had it set.

Great. But why then would others adjust to the tighter end of the range? As far as I can see this would be counter productive, not only potentially damaging but also shorten the adjustment period?
Are there performance benefits? Again common sense tells me the opposite would be true as the capacity would be reduced?

Exhaust valve clearance
 

I remember reading somewhere that it is possible to adjust the exhaust valve clearance without removing the radiator or draining the radiator. How is this possible?

Undo the radiator mounts & move it forward leave the coolant pipes on & cooling system full no need to drain it.

I guess one might err on the tighter side of the acceptable range because of wanting a quiet, less "tappety" engine. The risk is, as you suggest, that as the valve seats regress, they will become over-tight sooner as there is no room, or spare capacity to allow for this.

Anywhere within tolerance will not be detrimental to performance, only if the motor runs outside the clearance range will issues occur.

Some of the symptoms associated with tight valves:

They won't close properly, resulting in loss of compression and power and there is a risk of burnt/melted exhaust valves and engine damage. Poor starting and rough running, particularly at tick-over. Worse economy. The top end will run quiet.

Some of the symptoms associated with loose valves:

The valves won't open fully, so exhaust gases won't be scavenged properly on the exhaust stroke and a full charge of fuel/air may not be drawn in on the induction stroke, all meaning a loss of power. Poor running at higher revs. Worse economy. The top end will be noisy.

+1 No need to remove radiator on the Z as Kev says. There is enough flexibility in the hoses to get the room you need, but you do need to be fairly dextrous!

Exhaust valve clearance
 

Managed to get it done in the dark with a torch. Not without event though, one of my sprocket cover bolts broke of in the hole.
The hardest thing was getting the feel for the clearance with the feeler, and I'm still not sure if it's correct or not. The clearance seemed way out on both the intake and exhaust

Valve clearance settings
 

I think I have over loosened my exhaust valves. The power output is okay but there is a clear tapping noise coming from the engine.
I'm i okay to leave as is?

This is doing my head in, I really can't be sure if the sound was there before or if it is an okay sound.

How are things now? Has it settled in or are you still concerned?

I'd just like to ask what your mileage is? And what prompted you to do the clearances.

I'm at 14,500 miles now and i know for a FACT that valve clearances weren't done by my dealer at my 12,000 mile service (but they should have been!).
So I'm thinking of doing it myself... probably this week if I order new O-rings.