Church of Choppers Blog

All About The Honda RC51 SP-1

 

For those who dream of lean

A totally unscientific piece of research, conducted in pubs, pit lanes and grandstands throughout the country, inconclusively proves that eight out of ten riders consider buying a Honda SP-1 at some time in their lives. They imagine lifting the garage door to find a glossy V-twin whippet of a machine balanced gracefully upon paddock stands, of prepping and tweaking a proper race bike. But most of all they dream of lean and drive, drive and lean.
Nothing out there feels more like a race bike than an SP and, with its kit off, nothing looks more the part. Honda’s RC51 SP-1 is real racer tiny and HRC serious from its rough-cast engine cases to the tip of its Spartan tail. Just in case there were any doubt over the SP’s purpose in life, Honda slapped ‘racing’ on the side in big yellow letters. They could also have added ‘Ducati-beater’, had they had the neck, because in 2000, following a decade of utter Ducati dominance in racing’s premier four-stroke class (nine consecutive WSB constructors’ titles – and counting), Honda were taking on the Bologna mob at their own V-twin game.
Round one took place in print. A new Honda homologation special, HRC badges and all, had the motorcycling world salivating like an otter in an eel shop. An HRC V-twin, designed specifically to go directly for Ducati’s throat, it simply had to be the best bike ever. If the proposition appeared simple, the reality was anything but…
The RC51 was cheaper (at £10k, by a grand), faster and more powerful than a 996. But there were criticisms aplenty. On the road, testers griped about the over-sprung, under-damped (front rebound) suspension and moaned at the 100-mile tank range. But most of all it was the fuelling that drew the flack, being ‘snatchy’, over eager, especially when opening from a dead throttle. Combined with the rock hard front end, this made delicate control impossible on bumpy roads as the merest shock through the bars had the power coming in and out – not what was wanted with 122bhp trying to spin-up the tyre. On the track things were better, but still flawed by the fact the Honda would not hold a very tight line when hard on the gas.
All the criticisms levelled were valid, but with hindsight perhaps their context can be re-examined. HRC probably wanted to build a nose-standing bike with track geometry, but Honda, the suit-wearing soft bit, were busy trying to hold back the tide with their ‘no-Honda-road-bike-needs-a-steering-damper’ nonsense. Therefore geometry couldn’t go so radical as to flirt with instability. And the harsh road bits? ‘We’re HRC, we don’t care about touring range or fucking wing mirrors’. At least that’s what I’d like to think the men in overalls said.
Another problem for the RC51 was that we were comparing it to the base model 996 and not the equivalent homologation bike: the 996 SPS, costing ten grand more. Throw just half the difference at the Honda and it will more than compete.
You are expected to bin the big, heavy stainless pipes that demonstrate Honda road-quality. Of course you would revalve the forks and fit a height-adjustable shock. This bike should live on a paddock stand – that’s why nobody should care that the sidestand decks out at mammoth lean angles, necessitating ‘bank sensors’ like the nipples on an Eskimo wet nurse. Come on, you are buying the basis of a pure racing machine, get with the dream.
If you want softly, buy a VTR because SP-1s on the wing are not for those without serious backbone. First gear busts 70mph and it’ll go on to top 160. Stick to over 120mph and the suspension starts to work. Stick to over 120 on the road and you may as well have your central nervous system removed and placed in a pan with bacon and onions.
The 2000 WSB season saw the new RC go head-to-head with Ducati’s 996 and win – on the track, at least. Colin ‘consistent’ Edwards won eight of the season’s 26 races to take the title, though Ducati again took the constructors’ crown. Down at the dealers, however, SPs were sticking to showroom floors like road tar to a bellypan.
A counter-blow from Ducati with the 998R Testastretta again asserted the Bologna firm’s track supremacy in 2001, and hardly helped the Honda’s sales performance. This prompted a 2002 Honda revamp in the form of the SP-2 RC52.
Although appearing subtle, HRC’s modifications went deep, not least the refining of the fuel injection and the revising of damping rates. It was a better bike, easier to ride, but most of the modifications were primarily for racing reasons and in standard form it still wasn’t the world-beating road bike we’d been waiting for. Again our huge HRC expectancy could not be met by a Honda twin.
In race trim, though, the RC52 was again a winner in the hands of Edwards… remember that down-to-the-wire classic season finale at Monza? But again success on the track did not equate to sales.
The SP-2 bike is still in Honda’s official line-up and there are still older unregistered bikes that need shifting (brand new 03-model £7400). But even at that price it’s tough to justify buying one new when them pesky Eye-talians are now turning out such sublime road tackle as the 999 and RSV-R for similar money in the sales season.
But maybe in your world Ducatis and Aprilias are soft designer patsies, common as muck compared to SPs. And perhaps it’s imperative you have HRC-tech and build, essential you are riding a proper race-homologation model. The Honda SPs are without a doubt among the most exciting, involving bikes an enthusiast can fire down a country lane, so incredibly compact, so relentlessly fast, for gear-after-gear-after-gear.
So if you want the hardest of hard-edged V-twins you have a tough choice: SP-1 or SP-2. Whichever you go for, at least you know that while eight out of ten onlookers are thinking about buying one, you mustered the heft of testicle to put your money where their mouth is.

Isn’t it just a pumped-up Firestorm?

No, it goes way beyond that – have you seen those LCD clocks? Over 90 per cent of the engine parts are bespoke, featuring a far shorter stroke and wider bore for plenty of extra revs. At 100mm these were Honda’s biggest ever bike pistons in their day and hammered up and down at up to 10,500rpm in composite bores. A clever crank, with central oil gallery that helps feed the big-ends using the centrifugal effect of the spinning crank allows a small, light oil pump. We even have a couple of titanium engine cases upping the eye-candy.
On the fuelling front, gone are the VTR’s soft delivery carbs, replaced with rottweiler injection. Gulping great 54mm throttle bodies house pairs of four-point injectors. The ram-air intake that gives the bike its distinctive face is positioned at point for maximum effect, but that isn’t the cleverest bit. At lower rpm the intake is blocked off by an electronically-operated flap, helping boost low-down shunt.
On the chassis front, the SP-1 got seriously aluminium, seriously big-spar, rejecting Honda’s ‘pivotless’ palaver in favour of big bracing around the swingarm spindle area, to which the shock can be mounted. The headstock’s hollow to let air flow through.
Suspension is Showa and adjusts between hard and very hard. This was only the second ‘Onda to feature upside-down forks and bolted to them via ‘race mounts’ are the most glorious set of Nissin four-pots to adorn any road bike to date.
So no, if this thing’s a pumped-up VTR then an R1 is a mildly-tuned XS1100.

What’s with the rads?

These side-mounted cooling jobbies are one of the few design ideas the SP shares with its prehistoric ancestor, the woolly-arsed Firestorm. One of the modern 90º V-twin’s problems is keeping the wheelbase short and the steering racetrack-steep when the engine’s so long.
You can’t just shove it back in the frame – unless you’re building a TL1000 – as you’ll be seriously shagging with the weight distribution and the swingarm will be short, affecting stability on a compact bike. You could decide to conjure up a rotary damper, or something equally mental, to give you more space behind the engine, but you are still compromising weight distribution and all this could lead to bollox stability. Heaven forbid any such thing should ever happen. Simply increasing wheelbase obviously makes a bike too stable and tough/slow to steer.
Aprilia’s answer is to use a narrower, 60º configuration and to stand the motor upright, like a Harley, only nothing like a Harley. At Ducati, they have more experience in this department than anyone else and simply send a technician in SCUBA gear to Lake Garda, where he descends to a hidden chest of magic wheelbase dust, a small quantity of which is sprinkled on each machine as it leaves the production line.
Honda take a more pragmatic line, simply re-locating the cooling kit to the sides of the bike so the engine can move forward, and doubling up in numbers to compensate. Vents cut into the faring help direct plenty of air over our crinkly side panniers.

Just how impractical?

If you’re in the market for a nice little sports tourer, then this ain’t it. Start stretching the cables and those big throttles can shift gas at a rate of over 30mpg. This can mean fuel lights at 90 miles, but your battered arse will still probably wish the tank were eight and not 18 litres.
That jarring sensation through the seat, bars and pegs? That’s jarring, that is. Hard springs, heavy damping, plush this puppy is not. And there’s barely owt between arse bones and aluminium sub-frame to help out. Luckily a riding position designed for Frankie De Piggot lets the jockey shift bodyweight around, so it’s possible to move between discomfort zones. At least the motor’s smooth when not under full load.
On the practicality flip-side – it’s a Honda. The finish is excellent and as you throw the caringly crafted exhausts in the bin, please note that they’re stainless and should last longer than your average pope.
While the Ducatis throw up a few problems with starter motors, clutches and electrics generally, the Honda V-twin has a sterling reputation for reliability – though the electrics don’t like the wet, so get with the Vaseline. Cams are gear-driven, so there are no belts or chains to adjust (or fail).
Back to the bad/good news: this is the ultimate pillion torturing device. Harsh throttle response meets short wheelbase, high pillion pegs, gutsy motor and weight over the back – feel free to scream at the sky, Doris. And with those high pipes you can forget panniers for the sick bags.

So the SP-2’s just a tweak-over?

Wrong again, Hombre. Engine-wise there was no huge update, just tougher gudgeon (wrist) pins and reworked exhaust ports – to which tapered header pipes were matched. Lighter, thinner stainless end-cans rounded off the exhaust work. An electric fan was added to each radiator to keep urban temperatures in check and the oil-cooler moved further from the headers.
The much maligned fuelling got a complete makeover with huge 62mm throttle bodies (up by 8mm and big enough to deliver a calf through) and 12-point injectors replaced the four-jet items to improve atomisation. Not only did it remove much of the throttle snatch, but 4bhp was also gained.
Fractions of a kilo were trimmed from the frame, while at the same time it got stiffer engine mounts and a wider headstock along with bigger headrace bearings. The sub-frame’s walls got thinner, shedding half a kg and the swingarm lost a tad more weight than that despite being beefed up. It was now FireBlade-style, with a combination of press-forged pivot and right side, mated to an extrusion on the left.
Fork wall thickness was reduced to save a mammoth 30g, the damping rates were refined and at the back, the shock’s remote reservoir was repositioned to allow the fitting of high-level race pipes. And it goes on… shorter-stroke master cylinder for more feel, revised pads and new wheels.

New or used?

Are you a rider or a collector? If you fall into the latter category, or are some kind of biking fundamentalist who can’t stand the thought of another soul having ridden his metal bitch, then used is the way to go. As these bikes tend to be used little and loved a lot, there are stacks of them in near-virginal condition, many of adorned with the expensive trinkets of infatuated owners.
Just £4500 will get you onto the HRC, RC-series ladder in the rather delicious shape of an early SP-1 – try finding a good RC45 or RC30 for that sort of wonga. For that matter, try finding a really pukka 996.
A 5500-quid SP-2 will out-power a 996, even living with the Testastretta 998 if the going’s not too bumpy. Modifications don’t add much to the value to semi-collectables like this, so look for something that’s already had its suspension uprated and maybe a good pipe fitted.
Perhaps the sexiest option is to find a crashed bike (just found one online, £3k, rideable with full Akrapovic and P’Commander) and go for replica bodywork, whether using it as a track-day only machine or on the road. With the right modifications it’s then possible to put together something mind-bendingly slick and capable. Howsabout an endurance replica, or just a function-only, low–tune race bike? And best of all, if you go for aftermarket plastics you won’t have to live with the Essex chav paint job – just remember to order your genuine HRC stickers.

What are the best mods?

There are three areas that stand out for attention: the suspension, the fuelling and that clonking great pipe. A good place to start is with the forks. The Showas are good quality, but too hard for the road, so a specialist fork, re-spring, re-valve job is top of the list and should cost around £250.
At the back, a quality shock with ride-height adjustment will eat £500, but if you can’t stretch to that, a 4mm spacer placed between the shock and its top mount will go some way to sharpening turn and improving line-holding. If you do start jacking at the back, fit a quality steering damper which with fitting kit will see another £300 leave the wallet.
Mate a £300 Power Commander to a £600 pair of carbon cans with £60-worth of dyno time and you should be looking at a 4kg weight saving and 6-10 extra horses. A full two-into-two titanium Akrapovic costs £1300, but you should see at least 10bhp more go at the top end. Beyond these simple mods tuning gets very expensive and this isn’t an easy engine to work on. There are HRC engine internals around, but they’re very expensive, as is the expert labour to fit them, so you’ll just have to make do with your 135-140bhp.
For gawd’s sake put on some crash bungs, especially if you’re going on track where insurance may be in doubt. Trash your HRC wonder without them and you will cry when you get the repair bill. Lastly, treat yourself to some Harris adjustable rearsets (£260). Why not, you deserve them.

SP-1 riding

Sunny evenings, smooth, minor A-roads, intense riding. The faster, the better. Head down, tail up, throttles wide, the big pistons’ hammerings and deep airbox droning resonating in the thin-skinned tank. There is nothing in front of the rider and this feels like low-level flying.
What back end? It feels a bit like a mono-cycle, everything is about one wheel – the front. Low bars are close, the high pegs throw weight onto them and as the front end judders on the brakes I’m halfway to a handstand. Slick two gears down the ‘box to first for the 40mph roundabout, push hard on the left bar, push hard on the right bar, get on the gas and the steering goes neutral.
Thrapping it hard on the exit the steering finds the limit of right-hand lock as the front wheels unloads. A minor wiggle on landing, a small paddy as the gas does down over the white line… and on.
This is a bike that works best under power, needs to be kept balanced on the throttle to keep some weight off the front and quicken the turn. As compelling as it is demanding, the challenge is keeping the motor always spinning over 5000rpm where any deficiencies in the fuelling go as unnoticed as the few cars that are eclipsed in an instant (were there cars?).
Is it as quick as a current bike? Yes, but it doesn’t do it for you and it’s horrible on the brakes – the forks won’t let me get anywhere near the Nissin’s limits. Just how good would this be with some slick tube internals?
Fireblades feel sterile, R1s unreasonable easy, GSX-Rs unfeasibly fast. Ducati make some nice sports tourers, don’t they, bikes to be savoured like fine wines. HRC RC51s are more like a shot of ice-cold vodka – intense.
The Honda racing twin is just so incredibly involving. If I could just hold on to another 1000rpm through that left-hander… Pick up keys, unlock bike and go try it again.
By  Kar Lee