Hi, So what I tell is only from "my" experience... I am sure you will get many other opinions. Bottom line... you tune for what works best for your riding style. I "like" idle closer to engagement. Generally, drag racers like to see higher idle speeds. The Vmax should be engaging at 3800 +/-. Your spread is about 2300 between idle and engage. I set my idle at 2500 on my Vmax (my preference). Don't forget the 540 will show more torque than the Invader at lower rpms so raising the engagement and/or idle on your Vmax would not be as beneficial as would be an increase on your Invader. The torque/hp curves are much different for those two engines. Also, the Invader and Vmax use different needles and needle jets (same slide cutaway 2.5) so that will have an impact on your "low end" calibration. You will hear mixed reviews on the Kawi clutches (good and bad). Here's my take... You will find clutch misalignment, worn out primary and secondary bushings, cam slide shoes worn flat... you get the idea. It is quite a job finding all new parts for these clutches, so the low end "bog" is pretty common. You raise your idle... your engagement, or both and you bring the motor closer to it's power curve. You end up "pulling the sled through" all it's ineffiencies. The torque curve for the Invader will "start" at a higher RPM than the Vmax, so a higher idle and engagement would be beneficial. So... even though you have two piston port motors that "seem" comparable... they are not. You have different power curves and different low end carb calibrations - not to mention chassis weight differences (60 lbs+/-) and gearing! I am sure I have left something out. Others will chime in on this. Unless you are racing your Vmax or performing engine mods... leave it just the way it is (more fuel/trail friendly). Tory