YFZ 450 Jetting

[Ducman]

For all you new YFZ 450 owners, don't be a dumbass like me and jump right into jetting the YFZ carb thinking that you know what your doing since you did it already so many times on the banshee. It is way easier than the banshee. Seriously, you can change the needle, pilot, and main easily in 15 minutes, but it's not completely intuitive, at least not for me. If you haven;t pulled the air box lid off, the spark arrestor baffle out, and rejetted with the needle out of the YZ dirtbike, do it know! It is so easy, like I said, it takes 15 min on your first try if you read the directions and know the correct way to do it, and you'll shit your pants when your feel the power difference! Best of all if you order or get all the jets from the dealer individually it's only about $20 at the most.

 

 

First of all, dont try to take off the carb, you just loosen the boots on both sides and rotate the carb sideways. When I went to change the pilot and main I was a dumbass and tried to unscrew the small screws than hold on the bowl, every one I tried stripped the philips screw head because they were on so damb tight. I finally figured out you can access the main and pilot by taking off the large hex nut on the bottom of the carb. Unfortunately, I didn't see the pilot (in front of main but hard to see, deeper in the hole) the first time so after finding some instructions on the net I had to go back in and do that step again for the pilot. The instructions are in the link below. The needle is also super easy to change because the slide isn't connected to the throttle cable. Just remove the cover on top of the carb and unscrew the allen scerw on top of the slide that holds in the needle, pull out the old needle and drop in the new one.

 

Jetting for the YFZ 450 has been figured out for each particular combo of mods probably down to more of a science than the banshee, ie. with these mods (x,y,z) your jetting should be this (#xx pilot, abcd needle, and #xxx main)

 

 

On my wifes YFZ 450 I got a slip-on Yoshimura pipe, airbox lid off - jetting is #45 pilot, NCVQ needle (same needle that comes stock on the YZ 450F dirt bike and in the GYTR jet kit), and #170 main (one size bigger for colder weather). Holy shit the Yosh pipe is loud when you "get it on" and it friggin rips. If my 140 lb wife gets good at riding the YFZ I might be in trouble!

 

 

changing pilot and main jet

Grinding the fat end of the NCVQ needle isn't typically necessary for most mods, ignore that part

Replacing the Needle

 

Propper Jetting according to mods

 

Main Page - The DADDOG DOGRIDERS YAMAHA YFZ-450 FREE INFORMATION PAGE.

[00BANSHEE]

Good post Ducman. I learned alot from the Dogriders' website when I first got my 450.

[locogato11283]

jetting the 450 sucks. that carb is packed so tight in there its not even funny.

[00BANSHEE]

Look on the bright side. By the time you get to the carb to jet it you can send in your frame to have it powdercoated.

[banshee76179]

Look on the bright side. By the time you get to the carb to jet it you can send in your frame to have it powdercoated.

[Ducman]

jetting the 450 sucks. that carb is packed so tight in there its not even funny.

Yeah, if you actually wanted to get the carb out of the frame I don't have a clue how you would even go about doing it, but I thought changing the jets was easy and goes pretty quick once I figured out how it was supposed to be done. Correcting the stock jetting which is too lean mankes a huge improvement on how the engine runs especially on the bottom end.

[racer]

Look on the bright side. By the time you get to the carb to jet it you can send in your frame to have it powdercoated.