Although extremely competent for a road bike, the NSR250's brakes are virtually always overlooked!

During model evolution, the braking system was the only area Honda never deemed it  necessary to update too drastically. MC16's were equipped with twin piston sliding callipers and semi-floating disks, but after the change to 4 piston callipers and floating discs on the first MC18's, the brakes have remained largely unchanged. The calipers are widely used throughout the Honda range, and even the "updated" MC28 callipers are simply parts bin items similar to the later Fireblade and VTR1000!

MC18 and MC21 calipers share pads with the original (round headlight) CBR900RR Fireblade, and for the MC28, simply use "late model" Fireblade pads from the equivalent year!

Each NSR has had excellent brakes for its era, but since the R5K (series 2) MC18 they can be considered exceptional! These are essentially the same brakes used, as mentioned, on the Honda superbikes

The main differences between the larger bike's systems and the NSR's is the bore size of the master cylinder and the disk size. The most cost-effective upgrade for the MC18 and MC21 is fitting of VFR400 NC30 forks and disks. The forks are the same 41mm diameter as the NSR, and the 296mm disks bolt right up to the NSR wheel. The NC30 uses a similar caliper to the MC18 and MC21.

The above can also be applied to the MC28, but you will of course end up with the earlier style calipers.

Brake fluid is hydroscopic, meaning over time it absorbs moisture. As the brakes are applied, the moisture boils and tiny air bubbles form, the result is a lever that feels 'spongy', or in extreme cases, will just squeeze back to the clip-on! Not a nice sensation! The fluid should be changed every season, or even more often if you race or regularly attack track days. Generally, the darker the brake fluid, the sooner it needs replacing. Just open a new bottle and you will see that new brake fluid is almost clear.

There are 3 common types of brake fluid:

Do not mix DOT-3/DOT-4 (Glycol based) fluid with DOT-5 (Silicone based) fluid.

In the interests of safety, if changing from DOT-3/DOT-4 to DOT-5 or vise-versa, make sure that the system is thoroughly flushed, and when changing or topping up your system, only ever use fluid from a new, sealed container.

It's a popular misconception that the stock OE (original equipment) pads need "binning"! For the majority of riders the standard pads are superb. Remember, they are specifically designed to work with the disc material, the bike, and its intended riding style. If however, you and your bike habitually see the aforementioned track days, or are "the last of the late brakers", you may want to consider an upgrade.

Another reason for switching pads is the cost of the genuine replacement, Honda pads can be up to 50% more expensive than aftermarket options.

HRC replacement pads are available in racing compound (part# 45105-NKD-970) and endurance compound (part# 45105-MN8-006). These pads will suit MC18 R5K through MC28. As you would imagine, the racing pads wear considerably faster than the endurance pads but do warm up to optimum temperature much quicker.

Various manufacturers market aftermarket pads, Brembo, EBC, and Ferrodo, to name a few, and each often come in different grades allowing you to choose a characteristic to suit your own particular application.

A sports compound such as Brembo's Green Pad is recommended for fast road use over a racing compound. The racing compounds are designed to work more efficiently at higher temperatures, thus reducing fade, so are not as effective at normal lower speeds where they can't reach their optimum operating temperature.

Brembo Green pads are available in the UK from MPS (01626 835 835) part# BB-HO28 for the front, again suitable for MC18 R5K through MC28.

When replacing pads apply a little anti-seize compound such as "Coppa-slip" to the backplate and also to the pad retaining pins. The pad retaining pins should be regularly removed and cleaned to allow a smooth action, and also replaced every couple of seasons. 

If used under extreme conditions the caliper dust covers can be left off to aid cooling.

High on anyone's shopping list has to be braided lines, more often for looks, than functionality! Modern stock lines are more than adequate for the majority of riders, but aero-quip hoses DO look the business! The only serious problem with stock lines is the fact that they can perish over extended periods of time and the fittings become corroded. On average, 80% of the lines taken off road bikes are usually fine! This isn't to say that under the right conditions, a braided set-up isn't a superb upgrade though, and great attention must be paid to the braking system at all times. If replacing lines, braided steel is the logical replacement!

The name that will run off of most peoples tongue is Goodridge, other excellent manufacturers include Earles and HEL.

Finding brake lines custom made for the NSR range can be difficult, so persevere, and if you do have to have them made to order make sure you allow for enough free length for when the suspension is fully extended, the last thing you want is to have the front wheel in the air and the lines ripping themselves out of their sockets... it does happen, often!!

Most companies will supply a clear 'heat-shrink' PVC coating now, and it is highly recommended for keeping the braiding clean from brake dust.

Another highly recommended addition is a bleed nipple on the master cylinder, and an item included in the MC28's HRC kit. (HRC part# 45530-NX5-000) This makes bleeding the system much easier when replacing the fluid. As this is an RS125 part, it may need to be ordered through an HRC dealer. Alternative items are available from companies like Goodridge and Earles. 

The RS125 bleed bolt is longer than the NSR's so use 2 copper washers for each join instead of 1, as spacers.

The calipers are one item on the NSR that really don't need changing. As mentioned earlier, they were originally designed to haul up a lot more weight than your average 2 stroke race rep! The best thing to do to them is to thoroughly clean them, inspect the dust seals for perishing, the pistons for any signs of wear, and the piston o-rings for fluid leaks.

When inspecting the calipers remove the brake pads and carefully apply a little pressure to the brake lever. Watch for the pistons moving. Don't squeeze the lever too hard or the pistons will pop out of their housing. The pistons should retract very slightly as you release the lever pressure.

If you are looking here for a "how to" on servicing your calipers, take your bike to a qualified motorcycle mechanic!

The brakes are the single most important system on the bike and any work undertaken to them MUST be done by a fully competent mechanic!

The stock discs are again, very good, and most riders should never feel the need to replace them until they wear to their service limit. As long as the pads are replaced regularly, i.e. not left to wear right down to the 1mm service limit each time, and the calipers kept clean so as their action never becomes sticky (and hence allowing the brakes to "bind"), the discs should easily last 60000kms, even if the bike is aggressively ridden!

VFR400 NC30 disks can be used on the NSR, but this necessitates the use of the NC30's forks due to the larger disk diameter. The conversion works extremely well though!

Another option is to use VTR1000 disks. These bolt straight to the NSR's rims and require only a small modification to the calliper mounts to space them correctly. 

One of NSR-WORLD.COM's track bikes is currently undergoing this same upgrade, and a full "How To..." will be published soon!

A conversion that shouldn't be ruled out, funds allowing, is the complete Brembo kit available in the UK from MPS. This kit is intended for the CBR900R Fireblade, but as the early models brakes are effectively very similar to the NSR's, it should be a fairly straightforward transplant. You will probably need to upgrade the forks to VFR400 NC30 items though, as the VFR has larger diameter discs to start with, or you may find the adaptor plates may not be tall enough! As always, careful measuring is highly recommended before any critical component is modified or replaced!!

An interesting note, if you fit the VFR forks this will also give you the opportunity to fit a 3.5" front rim too, if you are so inclined. You can then make better use of a wider 120/60x17 tyre if you wish, or a suitably sized slick if racing.

The kit includes a master cylinder, 320mm discs, calipers and adaptor plates, and braided hoses, but you will need to feel a little extravagant as the price is around £700 ($1100). MPS are in SW England and can be contacted on +44 (0) 1626 835 835.

ONCE AGAIN, NSR-WORLD.COM RECOMMENDS THAT THE BRAKING SYSTEM ONLY BE WORKED ON BY A FULLY QUALIFIED MECHANIC.