How's the best way to tune the suspension? Any methods, tips, tricks?

Hiya - just put 20 psi in the front forks to stop the dive under braking, also dropped the forks thro the yolks 5 mm to get it to steer quicker, now much better!! :)

Meant suspension wise, how to set up preload etc.

But still good recommandations.

whats wrong with the suspension lasse,is it too soft ? too hard ? are you perpared to spend money to make it right ? are they due a rebuild as in how long have you owned the bike and when did the fork oil get changed last ?

suspensions the best mod for these bikes,even something like changing the rear linkage for the rick oliver modded one makes a change for the better,but for the best results (as long as your not 9 stone in your full riding gear) its probably best you upgraded to stuff designed for you weight.
for the forks you could try stripping them and rebuilding them with heavier oil but i have been told this doesn't always work the best,if you could you should try ricks spring kit in the forks and new seals/10w oil fit and forget...

the rear units are normally pretty shot.but ask about in local bike shops to see if someone can rebuild the units with a heavier spring (more suited to you size and weight) or if you can look out for an RS250 shock on ebay,get it resprung and modded to fit or if you can buy a new unit,this will be brand new,sprung to your weight and in some cases height adjustable so you don't need the modded linkage and when you finally fit that 17 rear you'll just have to rise it a little and jobs a good one

try a rebuild on the forks first as i'm sure they are crying out for it,the modded rear linkage could be a good cheap start to help the back but in most cases the best way to get things to work is new units

I don't know if anything is wrong, haven't ridden other NC30'es and haven't ridden this for long, so I don't know right or wrong.

Fork oil hasn't been changed during my ownership, so that will be done.

Didn't plan on spending huge money, just tuning what I have.

As Rhory said..you need to know what is wrong with it first?

They can be sorted to handle really well but it is horses for courses as we all ride differently.

Indeed, I need to know right from wrong, but how does the bike or feel if it is set too hard etc. etc.

First thing I would do is to check the basic geometry, since it's pretty well known what will work for the nc30. Suspension settings are personal, but getting the geometry in the ballpark would be a good starter.

Springs will be dependant on the track surface, rider and bike weight etc.

Then set the static sag front and rear. Other settings will depend on the surface you're riding on and the type of suspension.

There are some good guides to setting up the suspension logically on the net.