I want to rejet my carb on a 04 400 sportsman. bogs at mid throttle. It has a 172.5 main jet, how much should I drop? Should I lower the pilot jet as well?
thanks.

 

pilot jet only works up to maybe 1/4 throttle. if anything i would maybe think dropping your needle? are sure its not the clutching doing it ormaybe a worn belt? just an idea

 

new belt, serviced clutch, this is an intermitent problem, worse when warm temp. works great in fall/winter. punch it from stop position it is usually ok, if you let off and try to accelarate it bogs. no sputter, doesn't stall jost won't go. tried different carb, cdi.spark plug all the usual stuff.

 

Have a Tech bulletin on the early 04 400's about jetting and running rich,have to recheck but I believe jetting should be on the main 165,pilot no change.(0-3000 ft elevation) 172.5 would do better in winter because of dense cold air,but would cause rich problems as you say when warmed up in the summer(too rich) 165 0r 167.5 probably better choice!

 

my main jet is a 155.. on a 99 sp 500.. and my old plug was sooted bad.... how can i even this out

 

152.5 to 155 is correct main jet on the 99 500,blackened plugs mainly come from excessive needle and seat and probable needle jet and jet needle wear not usually jetting problems. 152.5 is the stock jet,but a 155 shouldn't affect it that awful much The old 425 magnum was bad about eating up needle and seats also,doing the same thing,black, carboned up,fouling plugs. Since its getting older possibly wouldn't hurt to drop the needle position ONE clip also after you check the carb out,may even give it a little more zip!!!!!!