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Hi, Im thinking about getting an RC51 but I was wondering what the difference is between the early SP1s and the SP2?
 

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My understanding is that suspension and brakes are improved on the SP2 as well as fuel injection. The SP2 uses adjustable Showas front and rear. I don't know about the SP1s.
 

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My understanding is that suspension and brakes are improved on the SP2 as well as fuel injection. The SP2 uses adjustable Showas front and rear. I don't know about the SP1s.
FI, frame, swingarm are the major updates from the Sp1 to Sp2. The suspension on the SP1 is also Showa and fully adjustable....however, all of the SP1's and SP2's can use a suspension upgrade. Send the forks to Dan Kyle (or buy Ohlins R&T's) and either get a Ohlins or Penske rear shock and you'll be good to go.
 

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FI, frame, swingarm are the major updates from the Sp1 to Sp2. The suspension on the SP1 is also Showa and fully adjustable....however, all of the SP1's and SP2's can use a suspension upgrade. Send the forks to Dan Kyle (or buy Ohlins R&T's) and either get a Ohlins or Penske rear shock and you'll be good to go.
Do you know for any other engine differences...other than EFI?
 

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This little article details changes in the SP2 RC51 which came out in 2002. I've wanted this bike since it's intro in '00, I'm glad I waited, the SP2's seems to have been tweaked just a tad nicer............................. John

Whatever the multimillion-dollar factory riders want, it seems they get. And if any of those changes happen to benefit street riders, well fine--but it's almost an accident. So it is for 2002: A multitude of tweaks have arrived to make the '02 RC51 more competitive on the track, but the trickle-down effect is that the bike is now much improved for puck-wearing plebes.

For '02, Honda chose to tweak the engine a bit, put the entire bike on a part-by-part diet and significantly revise the suspension, chassis and swingarm. Down in the engine room, the throttle bodies have been supersized from 54mm to 62mm, and the two injectors feeding each combustion chamber now sport 12 laser-drilled jets, rather than the four little garden hoses of the previous bike, for a finer spray. The injection and ignition mapping were tweaked, also, resulting in throttle response that's as smooth and creamy as a nougat filling. (Don't tell Nicky; he's got a sweet tooth.) The new motor feels same-same in terms of power output; Honda claims a two-horsepower increase for 128 hp at the crank--but the low-rev snatchiness is nowhere to be found.


The engine is warmed over, but as Honda's Doug Toland said at the intro, "All of the 'magic' of this bike is in the chassis." The new Pro Frame looks similar to last year's and has the same amount of rigidity, but weighs 260 grams less and is more linear in its absorption of stress thanks in part to the new stamped engine hangers (previous units were cast). Also new is a steering-damper boss up by the steering head, but on the stock geometry you'd be hard pressed to make this bike shake its head on the street or track.

Even though the steering-head angle has been reduced one degree to 23.5 degrees--the steepest of any Honda--the RC51 feels planted at all speeds, even at 130 mph through Willow Springs' infamous Turn Eight. There you sit, tucked behind the splendid new windscreen that's 1.2 inches taller than last year's, sensing no instability from either end of the bike. Of course, the new swingarm (890 grams lighter) is 16mm longer and aids the stabilization effort.


Right above that sexy new swingarm is a revised shock (115 grams lighter). It's been repositioned to allow room for aftermarket exhaust systems, but also had its linkage ratio tweaked (4 percent softer on the bottom, 5 percent softer on top), even though spring rates are the same. Nine percent more compression damping has been added along with 11 percent more rebound. Up front similar tweaks have been applied. The fork (145 grams lighter) is now 9 percent softer on compression, up 16 percent on rebound, with the same spring rate. Fork travel has also been increased from 4.7 to 5.1 inches. These changes make the bike feel plush and controllable--a far cry from the wooden feel of the previous bike. The suspension is simply awesome now, soaking up midcorner ripples yet never getting out of line or doing anything untoward.

Steering effort is drastically reduced on the new bike. The RC51 is no 954 in terms of flickability, but the new bike turns in with an ease and precision that's head and shoulders above the old bike. Pick your line, shove the bar and you're there. The previous unit's brakes were fine, but the new four-piston jobbies are even better. The old brakes were extremely progressive--once activated you only had to move your finger a smidge to stop the bike. The new brakes are totally linear and require more lever travel, providing better feel, easier modulation and more feedback.


Speaking of feedback, the RC51 comes wrapped in a new flavor of Dunlop rubber named D208. The 208s are quite soft for a street tire, which allows them to heat up quickly and throw down GP-like grip. Feedback from both the front and rear was excellent, with excellent straight-line stability and precise steering at high and low speeds.

Our only complaint (and we think some folks at American Honda's marketing department will back us up on this) is that the bike looks exactly the same as last year's. Europe gets a bitchin' white/grey, but we get the same paint job as before. If you go out and buy the "new" model with all the killer updates, you want people to know, but it's literally impossible to tell the two bikes apart from a distance.

Paint job aside, the changes made to the RC51 for '02 signify a Paul Bunyan-size step forward. Oh, did we mention the '02 RC51 is the same price as last year?
 

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FI, frame, swingarm are the major updates from the Sp1 to Sp2. The suspension on the SP1 is also Showa and fully adjustable....however, all of the SP1's and SP2's can use a suspension upgrade. Send the forks to Dan Kyle (or buy Ohlins R&T's) and either get a Ohlins or Penske rear shock and you'll be good to go.
Ditto on sending the forks to Kyle Racing. If there's such a thing as an RC51 Guru, it's Dan. GREAT work, VERY reasonable cost.
 

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Everything they learned in WSBK with the SP1 was applied to the SP2.
So technically, the SP2 is the better bike.
But for the street, either is great.
But...if you have an SP1, for sure get the Kyle Racing rear suspension link.
It changes the rear linkage rate from progressive to linear.
The SP1's were known for really stiff rear suspensions and the Kyle link changes that.
 

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For the SP1's, the Kyle Racing rear link a must.
It changes the SP1's progressive rate linkage to a linear rate.
Fixes the notorious harsh ride the SP1's have.
Has slight benefit for the SP2's as well, but not as pronounced.
 

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What about plastic? Are the SP1 and SP2 platics interchangeable with the frame changes? I have an 01 SP1 and I am shopping for plastic.
 

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I'm not totally 100% sure as I have an SP2, but I believe the side fairings will interchange. They seem to be physically similar in the service manual.

The lower inner fairing on the SP1 used 8 clips vs. 6 for the SP2.
There may also be subtle differences in the way the decals are placed, so they may not match with the upper cowl (fairing).

Any SP1 owners out there with input?
 

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I'm not totally 100% sure as I have an SP2, but I believe the side fairings will interchange. They seem to be physically similar in the service manual.

The lower inner fairing on the SP1 used 8 clips vs. 6 for the SP2.
There may also be subtle differences in the way the decals are placed, so they may not match with the upper cowl (fairing).

Any SP1 owners out there with input?
Even though I haven't mounted SP2 fairing to my SP1, I believe they are totally interchangeable.
I have studied their mounting points, the cable routing and everything is the same on both bikes
Only the V cowl that covers the oil cooler on the SP2 is deifferent ;)
 

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I know Makis revived this old thread last month, but did not the SP2 make marginally more hp than the SP1? Something like 3 BHP?
 

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I copied this from an old thread in Fireblades talking about the same thing
It's talking about the changes Honda made in the SP2's
I don't know how accurate it is, but looks legit...


Part
Difference
Reason for Change

Forks
Lighter Staunchion Tubing, Softer Damping
Stiffer, more compliant

Front Axle
Heavier
Change front/rear weight bias

Front Brake Discs
Thickness increased from 3.5mm to 4.0mm (Rotors Black on SP1 and Gold SP2)
Prevent warping

Front Brake Master Cylinder
19 to 17 mm
Better feel

Front Wheel
5 Spoke
Lighter

Steering Stem
Larger
Stronger

Steering Stem top nut
Increased to 41 mm (previously 32 mm)
Stronger

Frame
Different engine hangers (cast on SP1 and pressed SP2), swingarm pivot
Lighter, Stronger

Throttle Bodies
Increased from 54mm to 62mm
Better throttle response, more top end power

Velocity Stacks
Size Increase
Better throttle response, more top end power

Air Filters
Beneficial restrictor in left filter
Better throttle response, more top end power
filters cleanable

Injectors
New 12 hole design (previously 4 hole)
Better fuel atomization Smoother throttle response

ECU
32-bit CPU (previously 16-bit)
Better throttle response

Cooling System
Fan for each radiator, relocated oil cooler
More efficient cooling system

Seat Undertray
Redesign, ECU location change
Better underseat arrangement

Swingarm
Complete redesign, longer, lighter
Better rear grip and feel

Swingarm Pivot Inserts
different, Larger.

Chain
2 links Longer
Length increased to accommodate longer swingarm

Rear Wheel
5 spoke
Lighter than older 6 spoke

Rear Shock
Relocated resevoir, softer damping
Easier to route exhaust (after market makes), more compliant, lighter.

Windscreen
1.5" Higher
Better wind protection

Exhaust port shape
Now "D" shaped (previousy round)
more efficient

Exhaust Header
re-shaped
More efficient/Lighter/More top-end

Exhaust Cans
Redesign/Lighter
Lighter

Rear Mudflap
Redesign

Clutch
First Friction Disk has larger Diameter, addition of Judder Spring
Better Clutch Action
 
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