Define "correctly".
If you mean set up with a big enough margin of error (i.e. rich enough, low enough compression and retarded enough timing) to be on the safe side at -10*c at sea level with a sea mist then that is definately true. But take that bike into Death Valley at 40*c and 10,000ft and see how it runs.
But to be fair not many people seize totally standard NSRs.
Or if you mean set up correctly for the conditions at the time the same is true.
The problem comes when you play with the settings in a quest to improve either power, ridability or both. Then you ride it in 20*c colder conditions than you set it up or at wide open throttle for miles or both.
A good demonstration of the margin manufacturers build in is shown by the power the bikes produce;
Most of the full power 250's claimed 55 bhp, this will be an at the flywheel figure and they can be ridden hard anywhere within reason.
A carefully set up NSR on standard pipes and carbs can make 60-65bhp.
That's near 20% more power basically from running it leaner.
And the ridabilty factor, I've spoken to RGV and RS250 boys who've run proper UK full power settings and they can't believe how tractable my bike is (was ), in mid summer it really did pull totally cleanly from 3000 rpm at pretty much any throttle opening.
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