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Discussion Starter #1
Hi guys,

Browsing through a parts catalogue and I noticed different part numbers for thefron calipers & brake pads from SP1 to SP2. Any idea what the physical difference is ?

Thanks for any feedback
 

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The front rotor thickness was difference between SP1 and SP2 (.5mm thicker).
If there is any difference, there can't be much.
 

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The SP1 caliper pistons are 34/32 and I think the SP2s are the same though they may be different as the SP2 has a 17mm master cylinder where the SP1 has a 19mm.
 

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Discussion Starter #4
That's interesting. I am quite surprised that there are so many differences between the two models. The second injectors, lighter wheels and the like can be expected but disc & calipers are fine tuning on the part of Honda.
I'll have to be careful when purchasing used or new parts for my bike.

I just purchased a 2000 model and have been reading up quite a bit on this website. You guys have some really good feedback to help fellow riders.

Thanks guys
 

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I don't think they changed the calipers at all, only the master cylinder piston diameter for different feel.
The calipers are the same as the ones used on the CBR600F4i of the period, except the RC51's are gold and the 600's are black.
They are actually very good and light calipers for non-radial design.
 

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also the 929 and 954 have the same gold calipers (one of them may have had 32/30s), the 929 and the SP1s had 19mm MCs and then the 954/SP2 went to the 17mm. As subsailor said you'll get different feel, slightly more lever travel / slightly less effort required. I've found all the parts can be easily interchanged.

I think the brakes on my SP1 are as good as anything else I've ridden.
 

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The 19mm piston diameter is usually desired on the track over the 17mm diameter as you want better feel what the brakes are using as opposed to leverage.
The smaller diameter is better served on the street.
For better pad bite with the larger diameter piston, the use of pads with harder bite can be used (such as the HRC hard bite pads).
The newer model Brembo master cylinder has the option of changing leverage ratio to suite rider preference.
 

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You are correct.
I looked at the caliper and master cylinder specs in the service manual.
SP1 - Master Cylinder 19mm, Caliper pistons 34/32mm
SP2 - Master Cylinder 17mm, Caliper pistons 32/30mm

SP1 Brake Rotor Thickness 4.5mm
SP2 Brake Rotor Thickness 5.0mm
 

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Discussion Starter #10
Hmmm the calipers on my recently acquired 2000 RC are black...leading me to
want to investigate my brake parts to be sure there wasn't some swapping going on
at one point in it's previous life.
Either way, I will let you guys know how it brakes once I get rolling again in the spring !
 

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Honda (and other manufacturers) is known for recycling parts amongst it's various models.
It makes a lot of sense from a manufacturing standpoint.
 

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Haven't been here in awhile but, I saved a posting back in 08 about this very subject from a member from here! CBXJOHN So, Here It Is!!!

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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