lost a piston a couple weeks ago, so for precautionary measures put 400 main jets in it to make sure it would not run lean. i had it back for about a week with the new piston running it with the 380 main jets, (because the 400 main jets were on order) and it was running perfect. took it to the shop and got the 400's installed a couple days ago and ever since it was running like crap, once it got up over 6000 rpm it was fine but when i let off the throttle when the rpms drop between 6000 and 4000 the rpms would jump back and fourth like it didnt want to rev down and sometimes when at low rpms it would bog and feel like it was cutting out on one cylinder. i took it back yesterday and got the fuel screw adjusted, but that didn't make any difference. its at the shop today and the 380's are going back in it. im sure the jetting is the problem because before the jets were changed it ran perfect. i am running v force 3 reeds, an aaen pipe , and an mbrp silencer, are 380 main jets rich enough for this?