[jjj0923]

Has honda mades any substantial changes to the RC51 engine since it's introduction?

If so - what changes and how has HP changed over the last 5 years.

The RC51 was just being introduced when I was ending my racing career on a Ducati 916 and I've been out of bikes for the last 8 years concentrating more on high performance boats. It's time to get back into bikes.

thanks in advance...

Jeff in Maryland

[Pete]

The only changes came in 2002; today's RC51, except for graphics, is the same as in 2002. Here's an excerpt from RC51.org explaining the changes:

Main diff in 02 is they went from 2 4 Hole injectors per cylinder to 2 12 hole injectors per cylinder. Creates better top end. Obviously a different ECU to go with the different injectors, but they are not interchangeable between 00-01 bikes and 02+ bikes, unless you also change the throttle bodies. Hence you can upgrade an 00-01 RC51 to the 02+ throttle bodies if you change the throttle bodies and ECU to an 02+.

D-Shaped Exhaust ports on 02+

Lighter and different shaped swingarm 02+

Lighter 5 spoke wheels 02+

Differnt fork internals on 02+ although I'm not certain they were any better, just different. I actually preferred the 00-01 forks over the 02+ forks.

Went with a right side magnesium side water casing in 02 vs aluminum in 00-01 to shave a few ounces.

Went to 2 cooling fans in 02 to help cooling issues and it ended up making it worse. Not sure if they kept the 2 cooling fans in 03+

Different header shape to maximize d-shape ports. Slightly different exit points for rear exhaust join than 00-01, so they are not interchangeable. You can put an 02+ header on an 00-01, and vise versa, as long as your using the appropriate year muffler or slip on.

Aluminum fairing stay on 02+ rather than steel one on 00-01 to save a few more ounces.