I have tried to search the forum for the answer but got some different opinions.  What I was looking for is the part number for a #55 pilot jet on a 2005 S40.  I went to the dealer, twice, and got the wrong one both times.  The first was a long and slender version, obviously not for the S40 and the second had a number of bleed holes on it.  After installing the second version, I can only ride about 1/2 mile before it just dies and refuses to start.  I have also developed quite a backfire (somewhat like a shotgun) now.  The part number was KM555.  When I looked it up, it seems to be for a Kawasaki, also with a mikuni carb.  After reading various posts, someone recommended part number N151.067, an OEM part for CV carbs.  Someone else recommended a pilot jet with bleed holes.  I am a little confused as you see.  Does anyone have any idea which pilot jet I need?  Has the N151.067 worked for anyone else?  Thanks  for your help.

Yeah.  I tried that too but they still got the wrong one.  I called the parts dept. at Ron Ayers and they said they could sell me one but they'd have to order it.  I asked fore the part number and they said they could give it to me tomorrow.  Hopefully that will end this question.  Anyone have any experience with the KM555 part?  It says it is for a VM 22/210 carb.  Would that make a difference?  Isn't the BS40 a CV carb?  Not that I know the difference...

The "bleed type" jet you have is Mikuni # BS30/96, and the Sudco # 004-064 for that  #55 pilot jet.  The #55 jet is plenty rich for your Savage, but you have some maladjustment in the carb or an air leak in the exhaust system which is causing the backfiring.