56sav wrote:I recently bought my first motorcyle, a '97 NSR-150.

I keep the tach between 4-6K RPM and never race it.

Please don't take this the wrong way.
Why the hell did you buy a 2 stroke if you never take it over 6k rpm?
That is what these bikes are designed for and where all the fun begins.
Most of us try our best (on the road, trying not to break the law too much) to keep the revs above 6K rpm.