Reliability and maintenance. _________________ MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball
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. _________________ Andy.
NSR-WORLD.COM
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I had a race MC28 at 75hp ten years ago. This was on 100 octane gas with a fair few mods. It also had ram air, but that was never tested on the dyno because we couldn't make 100mph wind. My MC21 street bike made 74hp on unleaded a couple of years later. This was thanks to a couple of extra porting tricks I'd learned.
A couple of years ago I fitted RS cylinders and heads to an engine, running the NSR pistons and a set of special pipes. It made 76hp.
The RS (NF5) score well in the internals department as Andy says. everything is lighter and more precise, with lower friction.
The porting of the RS can be closely matched on an NSR, but you'll never get it quite the same because of the NSR's ropey RC valve design. The RS is much better and fits nice and flush with the port when fully open. I spent hours welding up and dressing the NSR RC valve for the 'perfect' fit, but it wasn't good enough. Did gain a pony at the top though.
Basically, The RS is a better design (for it's intended purpose) than the NSR, and as such makes more mojo.
Comparing my 2000 RS to my 1994 NSR, here is what I noticed:
The NSR powervalve design is much less precise. In fact, most all the tolerances on the RS seemed much more precise, and machined to a higher quality. The RS exhaust port is larger and causes the rings to wear faster. The NSR is hampered by a large flywheel, generator, and kickstart system that robs power from the engine. In fact, I would bet the NSR tranny is built to a much lower standard and uses heavier parts, which rob power.
Basically, the NSR overall design steers more towards reliability, and the RS toward performance. This design goal effects almost every piece of the engine. To design the NSR to pump out 90hp would dramatically effect the reliability. It was never designed for that much.
And the porting is different. My RS had NO power below 2500rpm, and revved to 14k. That would totally SUCK on the street. _________________ Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS
No, I think thats what me and Andy are looking for! Touch that fuse paper and hold on
Andys didnt have any power below 8k, and i mean noooo power. Not to be confused with monkeys bike which just dont have any power at all.
Back to the topic mind, the best road race 2 stoke ive ever riden was a 1998 RS250.. pulled clean from tick over made almost 80bhprw and was oh so smooth. _________________ If I have to take the carbs off once more...
One day I WILL have an NRS... It bugs the hell out of Stephen because he just wants an RS on the street (ooh, and he was so close to achieving that a few weeks ago!).
I will be happy with the 70-75hp of a (fairly) reliably set up RS motor in an NSR chassis on the street and a powerband of 10000-13000rpm! _________________ Andy.
NSR-WORLD.COM
Please keep all responses to Forum posts on the Forum so that others may benefit.
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Matt, surely you could produce the desired 100mph wind after a night on the razz downing your local Thai brew... And a can of baked beans! _________________ NSR300R - Why did i ever have a 250...
If you can find him after a night on the razz on local Thai brew!
It's easy to find some of the lads... Scott V will be in the police house, Luke F will be in the dog house, but there's no telling who's house Matt will be in!! _________________ Andy.
NSR-WORLD.COM
Please keep all responses to Forum posts on the Forum so that others may benefit.
Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.
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