Before reading the following, your attention is drawn to the Disclaimer.
See Page 3 for a full list of specifications.
Restriction
Please note, this is not the same as the 180kph (112mph) speed restrictions imposed on Japanese bikes.
Both the UK and import versions of the NC30 are suitable for restriction to 33bhp, to comply with the category ‘A' licence. This is the case for all of the 400's listed in the 'Other 400's ' section. Restriction kits are available from FI International.
The simplest method of restricting the amount of power a bike can produce is by reducing the amount of air/fuel mixture that goes into the engine. It is 
cheaper and more reliable than lowering the rev limiter or restricting the throttle movement. It also happens to be the simplest to fit and remove. Restriction by this method is by far the most common and is achieved by placing washers in the inlet tracts between the carburettors and the engine.
The best way to look at an engine is as a big pump, with the pistons drawing air into the cylinders through the inlet valves, then pushing waste gases out through the exhaust valves. At this point it is important to note that air cannot travel faster than the speed of sound. When air (air/fuel mixture) is being drawn into the engine, how quickly it reaches the speed of sound is governed by factors such as intake tract diameter, valve diameter, valve lift and the pressure forcing the air in in the first place (airbox pressure). Once the air has reached the speed of sound, maximum flow has been achieved. In standard set-up, all of these factors have been carefully balanced to achieve optimum power output.
By forcing the air to pass through a smaller diameter inlet, as in the case of a restrictor kit, the air is forced to reach the speed of sound faster. The cylinder still wants the same amount of mixture to fill it, in the same amount of time, however the piston is attempting to ‘pull' (I use the word pull loosely) that amount of air through a greatly reduced gap. (See right, the top diagram shows an unrestricted intake, the lower shows a restrictor in place). Consequently, maximum flow is reached earlier and not as much fuel and air is taken into the cylinder. Effectively, you are giving the engine a nasty case of asthma.
With less fuel and air to combust, the engine cannot produce its designed full power. Less force is produced when the mixture expands. The rate at which the piston is forced downwards by is smaller, so there is less linear motion to be converted into rotary motion. This explains why redline is reduced; it is not solely governed by factors such as valve spring stiffness and crank/con-rod integrity. It can be seen that maximum power and RPM is very much governed by the speed of air in the inlet port.
Other results (beneficial results) of restriction are that consumables such as tyres tend to last longer, especially the rear as there is less power being transmitted through it. Chains and sprockets benefit similarly, and the engine is less stressed. Fuel economy also sees an improvement, as less fuel is being combusted. If you want to know what it actually feels like when riding, have a read of the ‘Riding Restricted' part at the end of the ‘Riding an NC30' section.
Suspension Adjustment
I can explain the theory of adjusting the suspension on the NC30, but I can't actually tell you how to set up your bike. A lot of it is down to what feels right to you. I dabbled briefly with my suspension settings, but without much luck. I then handed it over to the professionals to have it set up to my weight, since then I haven't meddled! Having the suspension set up to your weight is the best way to do it. This is because on older bikes, the suspension has worn a lot; so standard factory settings are pretty meaningless. The location and function of the adjusters described here refer to the standard (OE) suspension on a UK Spec bike.
Both The front and rear suspension on NC30's is adjustable in two ways: Preload and Rebound Damping. 
Preload is the amount of tension within the fork springs, prior to a load being applied. With too little preload, the bike would simply sag under its own weight, let alone anything else. Too much preload and the fork springs would barely move when you hit a bump (you end up with rock hard suspension).
Rebound Damping is a control of how rapidly the springs bounce back after compression. With no damping whatsoever, the springs would rebound so rapidly that you will be shot out of the seat at every bump. With too much damping, the springs would recover too slowly, they probably won't have returned to normal extension before the next bump. This will give see-saw-esque, appalling, handling.
Front Fork Preload
Preload adjustment on the front forks is achieved by turning the adjusters using a 14mm spanner. Turning them clockwise increases preload, anticlockwise decreases preload. You will notice lines on the side of the adjusters (depending how far in they are wound). These are an indication of the amount of preload applied. Always adjust left and right forks equally.
Front Fork Rebound Damping
The small slotted nipples protruding from the tops of the preload adjusters control the amount of damping. The adjustment turns in clicks (you will feel it 
when you start to fiddle!) Using a flat-headed screwdriver, turn the adjusters clockwise to increase the amount of damping applied, and anticlockwise to decrease it. Again, adjust both the left and right forks equally.
The type of adjustment available is the same for the rear shock, but the adjusters are in different places (see diagram, right).
Rear Shock Absorber Preload
The preload adjuster is located at the top of the shock absorber (see diagram). Firstly, you must loosen the locknut. To increase preload, turn the adjuster nut in a clockwise direction. If you want to decrease preload, turn it anticlockwise. Once you have finished making adjustments, tighten up the locknut; do not ride with it loose.
Rear Shock Absorber Rebound Damping
The damping adjuster for the rear shock is a little more difficult to access. It is located at the base of the shock, on the left hand side of the bike. Like the front forks, you will need a flat-headed screwdriver. To increase the amount of damping, turn the adjuster clockwise. Turn it anticlockwise to decrease rebound damping. Again you should feel “clicks” of adjustment.