First off, I would like to thank everyone for answering my previous post because it has been a big help to me and learning experiance!! I have another question that requires some guidence and help concerning rejeting my 2005 AC 400 auto.

I purchased several mods for my atv and I already did the muffler mod (not extreme) drilled a few holes and welded end cap back on, purchased a Jet kit and K&N filter with Prefilter.

What jet are you running or do you recommend I start with? The directions are as follows:

I ride mostly 3500ft and below, The following jet sizes are for 3000ft and below.

DJ132 stock exhaust
DJ134 aftermarket exhaust/quiet baffle
DJ136 aftermarket exhaust/high flow baffle

This is for 3000ft to 6000ft:

DJ128 stock exhaust
DJ130 aftermarket exhaust/quiet baffle
DJ132 aftermarket exhaust/high flow baffle

There is no comment in directions about K&N, so when factoring that in, should I use a smaller jet or bigger? Kit also comes with a 170 needle jet.

I was going to try DJ 134 first but wanted your imput before I install...!! Hope you can help and thanks again!!

 

The KN will make the mixtures leaner, so go one jet size bigger than was called out.
From there, youll need to go by the symptoms of lean and rich, to get the final tune.
I found this article to be about the best ive seen, when it comes to jetting, and it has the symptoms of lean and rich, so you can easily do the troubleshooting, and know which way to go with the jet sizes.
jetting how to

 

what are you trying to accomplish with a rejet this early in the engine life?