What size jets are you guys running on your YFZ's?

I have a full Alba pipe, K&N filter (no air box lid), and did the cam mod.

I have been running a 170 main, 45 pilot, clip on the #4 spot on the NVCQ needle, and 3 turns out on the air screw.

I pulled the plug out today after quite a few rides on it and it was a light milk chocolate color, which got me thinking to bump up to a 172 or 175 main? or should I move the clip on the needle?

The thing runs like a raped ape, doesnt pop or die, but it is extremely hard to keep at an idle, in neutral its ok, but as soon as you drop it into gear it dies.

Another thing that concerns me is the pipe glows about 6-8 inches away from the motor after it idels for a bit, but when running through the dunes and at higher rpms it doesnt glow as much. Any thoughts?

Thanks for all the input.

Ian

Hey Ian PM BeachHead, he will tell you what ours are jetted at, and we seem to run alright.......

run a 175 main and u can also go up to a 48 pilot. to fix the idle just mess with the idle screw. on the carb on the left hand side. normal for the header to glow.

I will pick up some jets next week, and probably end up rejetting it while I am out there.

Is there a big difference in one jet size? It runs good now, so I am just wondering if I bump up 2 sizes in both the main and pilot it might be a bit much.

your lead dude!!!

alba and sparks both make great jet kits...i would give em a call...

well the bike has had the pipe kit on it since dec '03, and has had the same jetting since early '04, but it has never idled right since then, it was running great earlier since I cleaned the carb, I guess I will just have to run it and have the spare jets and see what happens. I have had so much practice changing jets, I can do it in about 15 minutes now.

i used the sparks jet kit on my bro inlaws bike. damm thing runs like a dream! have u done the cam mod on yours yet ian??

yup, did the pipe and cam mod at the same time, the thing eats up most banshees, and quite a few other 450's, for some reason it really hauls the mail.

those bikes kick ass!!! id love to have one...i crack up when i see 400 riders...sayin how the beat a 450.

not gonna happen!!!!!!!!



call sparks for a jet kit...they will set u straight!!!

I already have lots of pilot jets, just missing a 172 and 175 main jet, they are only a couple bucks a piece and I can get them from Alba on my way home Tues.

true dat!

IM running ESR pipe/ESR intake/Cam mod and running 175MJ, 45P, 4th clip NVCQ (YZ), and runs good. I ride at Dumont, so around 800ft. For Glamis I would run 172

I was really suprised when I saw the 170 in there, I will definately switch to the 172 when I get it.

about the thing never idling correctly. have you played with the black idle screw on the carb?

All the 450s idle hot and rough. Is your idle low Ian? Usually have to set the idle high on the 450s. If the plug is a light chocalate color your main has to be really close. You can try and back out the idle air screw out another turn to help the idle. The set up on my friends bike is a lot different but is fast as any 450 i've raced. Rossier short pipe, cam mod, ESR intake = 50 pilot, 180 main, 4 turns out on the idle screw, yzf 450 needle on 4th clip.

When I first did the mods his bike wouldnt idle for crap either. I was told to go from 2.5 turns out to 4 turns out and that helped alot at idle. Had to turn the idle up to 1500rpm or so too to make it smooth.