Hey, guys,

Just drove my S40 home today and as a new bike rider I love the weight and the power.   My drive to work is all twisty backroads and it seemed like the 'cruiser' to get.

Can someone give me a 4-5 sentence explanation of the backfire issue, I noticed it a few times in lean/idle conditions (like engine braking slowly before a curve and twice when turning it off).  I suspect they are lean from the factory, but it seems a bit much?  It was cool today, ~60.

I am not new to these types of engines and have put a piston/intake cam/exhaust on my Z400 and jetted it with little problem.  The S40 looks simpler and it was cheaper so I plan on doing everything myself as soon as I get my FSM.

And anything else anyone would like to share would be appreciated, maybe soon I will be productive on this site as well!!!

Removing the white  plastic spacer will help. Also a larger main jet will help as well. It will take a little time to get things right. Search for white spacer and main jets. We are here to help. The jetting depends on variables. Will you be replacing the muffler? Will you be replacing the air filter? Stick with it you will get it set up right for you and the effort is worth it.

Thanks guys.  What I've seen is folks saying the white spacer which is from the needle which would have a 1/4 to 3/4 throttle effect or the mixture screw/main jet which would have a idle and over 3/4 throttle effect.  I might play and do both to cover the entire rpm range.

Any exhaust kits that include jetting for exhaust and stock everything else?  Is there a K&N for the bike?