carburetor jetting

[Quad723]

i just installed a new 14:1 pistonin my bike. i already had a hotcam stage 2, full exhaust, and uni air filter. Does anybody have any suggestions for main jet, needle, and slow jet that would help my bike?

[01boneless]

what jets are in it now? to lean to rich what???? id do a like 182-185 main 50 piliot and idk on the needle

[Quad723]

im pretty sure its a little lean, no so bad that it pops when you let off the throttle, but i feel like it has a little more "potential". I had a friend to tell me it needed a 180 main, with the clip in the 3rd notch from the bottom of the neeedle and air screw out two rounds from closed. I dont remember what jets is in it now but that is my plans for tomorrow is to pull the carb and find out.

[01boneless]

what makes you think its lean? ride a while and pin it in 4th gear and kill the engine to a stop pull the plug and see what color it is . white is lean, black is rich,brown is perfect :D

[Quad723]

ok, ill try that. another problem that makes me wonder if it is lean is that it spins over for a few seconds before it will crank, and suggestions on that?

[01boneless]

that has nothing to do with the jetting ive never had a electrick start 450 but ive heard that the starter brushes or bearings mess up in there causeing it to spin freely. never give it gas while trying to start!!!!

[Quad723]

yea giving it gas while trying to start it is not a good thing to do. i had to put one starter clutch in it bc of that before i learned what caused the starter to quit cranking it. but ill check out your tips tomorrow and get back with you, thanks for your tips you have giving me so far.

[01boneless]

yup no problem if you have a camera take a pic of the plug or just decribe the colors (best to start with a clean plug)

[grant14]

i have the same basic set up on my 06. except 13.5:1 piston. it was 185 main 3rd from the bottom on a hrc needle and 48 slow jet. i cant remember what the air screw was. Jetting was set on a dyno at see level.
fwiw,

[DnB_racing]

Originally posted by grant14
i have the same basic set up on my 06. except 13.5:1 piston. it was 185 main 3rd from the bottom on a hrc needle and 48 slow jet. i cant remember what the air screw was. Jetting was set on a dyno at see level.
fwiw, are you running a +06 fcr carb with Keihin original Jets?

sounds very rich ...the 04/05 carb does require main jets that large, or maybe dyno jets,

but most +06 fcr without larger valves and drag porting, only require 170 to 175 mains at the biggest.

there are some running that big but they have a very open flowing system..

the intake and exhaust have the biggest impact on the amount of air that is able to be pumped into and out of the motor.

the cam has very very little,

compression and porting and valve size and big bore has some impact, as does fuel octane and oxygen content,(unless your running oxygenated fuel then it make a big difference) but not nearly as much as the intake and exhaust

if your running a air box with a uni filter and stock intake, then check plug, as a 185 seams too big for your setup.. its definitely on the safe side,but you might be compromising some performance,but with winter coming your definitely not going to be to lean with anything 180 or above..

your better off changing your plug more often then fixing a seized motor

[Quad723]

I just checked my jets, all i have in it is a 146 main with a 42 slow jet. the plug is white. i did not mention in my origional post that i do not have any head work.

[01boneless]

pretty sure those are stock jets ! :eek2: i'd at least start at a 48 piliot 170 main go up or down from there and dont run it with those jets because you running WAY lean!

[DnB_racing]

Originally posted by Quad723
I just checked my jets, all i have in it is a 146 main with a 42 slow jet. the plug is white. i did not mention in my origional post that i do not have any head work. what year?

that does sound like stock 04/05, if so 175 or 180 isnt out of the question for that carb.. but like bonless said get them stock jets out;)

[Quad723]

ohhh yeaaa, thats what i was thinking. thanks for everyones help and advice.