I have a 99 Sport 400 that has----------hpd trail pipe---reed valve spacer---boysen power reeds---k&n filter----rcr airbox mod---head mod from rcr for pump gas-----works front struts---------right now i have the plain spring that comes with the pipe kit in my primary--a black spring from hot seat in my secondary----is this correct for all out acceleration??????????I am new to the polaris seen--still learning this cluth thing.Is there a spring you guys have tried that seems to work well with this set up???????Is a helix worth the $$$$$$$$$???????I am only looking for all out acceleration.I have an orange spring from rcr that is longer than the plain spring --it shifts later and works ok with my paddles on the back.It is actually faster in a drag race with my paddles on with the orange spring.Any suggestion will be very appreciated..

 

Please listen and do one thing. Buy a complete aggressive clutch kit for the trail pipe from HPD. The helix is as important as anything else on the clutching and has EVERYTHING to do with acceleration.It would be the best $160 you could spend. List the other springs on e-bay. You can probably get almost what you paid for them. Your gonna have different people give you different ideas, but I promise this is the best. Later when you trail port it, you wont have to change anything. Bubba

 

i second that too,get the "trail" HPD aggressive clutch kit for your trail pipe,all will be dialed-in right out the box,at least some fine adjustments is needed.the 40/36 helix is great for trail riding,the HPD
violet secondary spring work good too.weights should be 58 g.the primary spring is HPD red/yellow for trail package tough...
with proper jetting in the carb it will rip for sure,there is an HPD spring and setup for all out acceleration,but the higher shift rate and rpm will not be on tap for trail mods i toughts.