A low 2.5" spring force makes the engagement RPM close to idle (converse for high 2.5" force). If you want to rock crawl, or maintain driveability, select a spring with a low 2.5" force. Select at higher 2.5" force to raise engagement RPM for racing or competition pulling.

A high 1.25" force raises the RPM at shiftout, which means you will be reving higher as you accelerate. If you have modified you machine to produce power at higher RPM's than stock, a higher 1.25" force spring will help you use that power.

RPM between engagement and shiftout is determined by the tension between engagement and shiftout.

Channging the clutch weights will also affect engagment RPM, Shiftout, and RPM inbetween. Ask the distibutor of weights and springs for recommendations. Do not be surprised if what you change does not do exactly what you though it would. Many people use a trial and error approach to this.

Note that the same color springs from different manufacturers are different springs. Also some manufacturers springs aren't painted exactly like you would expect (EPI pink spring is reportedly not pink unless you look in just the right light). Note that Polaris primary springs fit Kawasaki (get them from hotseat).

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