These are the mods that I wanted to do but I would Like to Know a few things so that I do not Have to spend hard earned money needlessly.

I am intending to install a Uni filter and a Supertrapp exhaust along with a snorkel. Also improved cooling will be added to compensate for the increase in heat. The goal is to improve the ability of my quad to pull at high speeds and also work harder.

1) What kind of carb does a 2003 Honda 450 foreman Have? Mikuni or Kilein?

2) I do know that the stock jet is #130, so what would be the next two sizes up from that? 131? 132?

3) How does one count the notches on the carb needle? ( Where is notch one?)

4) What size and type of jet do I need to buy and what do I do with the needle to adjust for the mods listed above?

 

the stock carb is a keihin.
the next sizes up will be a 132 and then a 135. just remember to use keihin jets. dynojets and mikuni jets are also made. the different brands have different sizing techinques. so, a 150 keihin is NOT the same as a 150 dynojet which is NOT the same as a 150 mikuni.
most people refer to the top notch being one. if i had to guess there will be 5 total notches on the factory needle and the factory clip would be in position 3, but that is just a guess. this is how it is on 400ex's anyways.


i would probally start with about a 135 keihin mainjet. just remember, bigger doesn't mean better. the richer you go, the less power you will have given your not really lean on the jetting. for the needle, i would find out how many positions are on the needle. in the winter you are suppose to jet bigger (richer). so, in the winter, i move my clip down one position (this actually raises the needle one position) and in the summer i leave the needle in the stock position. some trial and error may be needed for this. i honestly don't know if you want to go up on the pilot jet or not. you may want to go up one size on the pilot jet. my carb has a fuel skrew located by the bottom of the bowl. turning the skrew out richens the mixture from idle to 1/8 throttle and turning it in leans the mixture out. this fuel skrew is a fine tune adjustment for the pilot jet. so, there is a good chance you might not need to get a larger pilot jet.

just so you know: i wouldn't expect a large power difference. my friend did these same mods to his rancher and he noticed hardly anything at all. it may feel like you have more power but it is mainly due to the sound and extra vibration of the new pipe. have fun. cal