The NSR is very edgy, even in stock form, which is why they're so good out of the box, and why they don't respond well to things like compression and ignition timing changes. The later models more so, but I would still always fit a taller barrel on the front cylinder.

The issue is the spark plug location is less efficient on the lower cylinder, being more offset so as to increase clearance for the front wheel. This means the flame path is less efficient, and the cylinder head & piston more susceptible to detonation. A slight increase in compression, should you fit a shorter barrel (and note, replated barrels have often been "decked", making them undesireably and measureably shorter) can have a very short life if unchecked!

We had a (very quick) forum member here several years ago, who was racing an MC21, and destroying 4-5 barrels a weekend for 2 season, if I recall correctly. It took best part of a year to convince him to go back to standard compression, and as soon as he did, he won the F250 championship with 2 weekends (4 races) in hand!
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Andy.
NSR-WORLD.COM

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