Kawasaki Motorcycle Forums - View Single Post - 900 Scootworks pulley

hharada · 05-13-2008

Sorry, can't help you with actual tach and speedometer readings.

I've put ScootWorks front pulley on my 900 LT. I find the difference most noticeable in gears 1-4. I believe there is a difference at 75 mph on the speedometer, but the combination of high winds the two times I've put it on the interstate so far and undoubtedly higher actual speed at the same speedometer reading has made the difference harder to grasp.

You may have seen the specs on the Scootworks pulleys. The front is said to reduce engine rpm for a given road speed by 5.9%, the rear by 6.1%. Per Scootworks, a combination of both pulleys gives an 11.6% reduction (Don't know where the 0.4% loss goes, but that's what they say.)

Assuming the numbers are correct, if 3500 rpm gave you a particular speed before a pulley change, you could achieve the same speed at 3294 rpm with the front pulley change, 3286 rpm with the rear change, and 3094 rpm changing both.

I don't know if their numbers are simply calculated, or from field tests which would take into account friction differences, etc.

05-13-2008	#2 (permalink)
hharada Cruising In Fourth Gear BTK Intermediate Join Date: Dec 2007 Location: Colorado Posts: 221	Sorry, can't help you with actual tach and speedometer readings. I've put ScootWorks front pulley on my 900 LT. I find the difference most noticeable in gears 1-4. I believe there is a difference at 75 mph on the speedometer, but the combination of high winds the two times I've put it on the interstate so far and undoubtedly higher actual speed at the same speedometer reading has made the difference harder to grasp. You may have seen the specs on the Scootworks pulleys. The front is said to reduce engine rpm for a given road speed by 5.9%, the rear by 6.1%. Per Scootworks, a combination of both pulleys gives an 11.6% reduction (Don't know where the 0.4% loss goes, but that's what they say.) Assuming the numbers are correct, if 3500 rpm gave you a particular speed before a pulley change, you could achieve the same speed at 3294 rpm with the front pulley change, 3286 rpm with the rear change, and 3094 rpm changing both. I don't know if their numbers are simply calculated, or from field tests which would take into account friction differences, etc.