just put wiesco 11 1 and hot cam stage one in two of my buddies 400 ex one was 03 and the other o5 did the 05 today 03 was a night and day diff but has to go with bigger jet 170 too small 05 is going to get broke in today so time will tell but both bikes have a noticable torque gain even only using 1/3 throttle so??? hope this helps ya

 

dont worry as long as it is not in motor u dont put those back in with hot cam ((spring and plunger))

 

you can get 11 1 piston shipped to your door 4 97.00 fron e bay