I have been tuning my 04 Trailboss to suit my riding style (40 somthing guy with a questionable back). I have installed Ricks stage one kit with the 1.475 main jet airbox vents and I had the Dalton black with white strip installed. The Black with white strip gave a very high engagement rpm off idle through half throttle. This worked well when doing very aggressive trail riding but was annoying when trying to putz around slowly or load onto the trailer. So I bought and installed the EPI pink spring as recomended by some of the forum members. This gave me back my low off idle engagement but leaves the rpm's to low at half throttle. Anyway, after much research it appears that the Dalton blue spring according to load pressures will give a low engagement off idle but then get more aggresive in the midrange. Is anyone using this spring? And are my assumptions correct?