cgallant wrote:My RS with porting, and custom heads was good for about 90 max.

The power delivery, chassis, suspension, frame make a huge difference in the bikes.

So does 14 years development!


Hardly fair to compare your RS to an NSR circa 1990 Charles!

The 1989-1992 RS250 makes a much better comparison, although they are still quite different animals. The motors though, which I believe is the aspect in question in Phatmc28's post, are very similar so it's a valid enough question.

The main differences in the RS's favour are, in no particular order:

porting

lighter internal components

electronics

fuelling (38mm carbs vs. NSRs 32mm)

exhaust design

There are other things to consider too, such as the fact the RS will rev higher/longer, the single-ring pistons generate less friction, and the type of fuels usually used allowing higher compression and/or different ignition timings.

As drschneider says, an RS of the similar era is much more likely to have been making 80-85hp (certainly NOT 100hp) and NSRs have been known to make up to 75ish hp. Even the first of the next generation privateer Pro-Arm RS250's were only making around 85hp.

At the end of the day though, the biggest single difference I personally reckon is the crank. The RS crank and con'rod bearings are rated to 14000rpm, with a sustained rating of 13000rpm, but the NSR is 13000/12000rpm respectively and normally makes peak hp around 11500-11750rpm. When you are at that level of tuning, 1200rpm can make a huge difference.
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Andy.
NSR-WORLD.COM

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