A good port job won't adversely effect the [new] rebuild schedule, although any increased state of tune necessitates an increased level of [preventitive] maintenance.

Our SS tune will give you around 65~66hp using stock components, and the proper 250 rush you would expect... it transforms the bike! A 300 kit will give about 65hp and a bit more torque than our tune, making it more like a 4-stroke. No comment about reliability though. You can read all about what we've experienced with them in the 300 section. Just don't expect a 20% capacity increase to give a 20% power increase. It's not all about the top-end though, as the cases need to be modified too.

The basic 300 kit is more expensive than our basic SS tune, but you do get a lot of new parts for your money. A 300 with Wiseco's and VHM's is getting on for double the price of our SS motor, and still won't give you 70hp, in our experience.

NSR250 pistons are approximately £85 in the UK, and rings are about £50, so in that alone you are looking at around £300 for a basic top-end rebuild. You should allow £350~400 for parts though. You may be able to source cheaper in the States/elsewhere, or you may not. A standard 300 piston kit is considerably cheaper, but you're not getting Honda quality components, and you will be replacing them far more often!

As Charles rightly says too though, there are plenty of other areas that can also be looked at. Weight savings, suspension, and brakes all need to be looked at. It's about optimising what you have, not about trying to compete with something in a completely different class, with 20~25 years of additional development, and over double the capacity.

At the end of the day, modern 600's are fast bikes. You only have to watch them at the TT now; they look like "thou's" of less than a decade ago, and besides, the NSR250 has never been about straightline speed anyway. Any idiot can open the throttle in a straight line, even me! A well-built F-III will kick a 600's ass still, but you're looking at thousands for a motor, and then doubling it, for all the other bits! Then you're looking at an HRC RS250 rebuild schedule. You only had to watch Jim Hob on his 125 or Moto3 round Donington at our last track day to see how power isn't everything, however. He was blitzed down the home straight by the the 1000's, and by the time they came round again, he'd exit the last corner ahead of them all again, just to be blitzed down the straight once more. Or to see Matt on Watfordhorn's NX5 chase down Shane on Steve's NSR500V... He made up a good half a lap on Shane in a 10 minute session, and chose not to overtake him! And Shane's not slow by any means!

If you're like the majority of us, and can't ride at a professional level, the simple fact is "performance costs". Some have sold NSR's for [usually] faster HRC RSs, some have sold them for 600s and 1000s... one even sold his for a 500 GP bike!
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Andy.
NSR-WORLD.COM

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