[blue streak]

Ok here is my set up 900 feet above sea level, 170 main, stock needle 5 th clip, YZ timing, fuel screw 3 turns, pea shooter removed, air box lid removed, it has a bad hesitation off idle seems lean to me. I think I might need a different pilot and or a different needle give me your thoughts. By the way this was my first time out with this set up and its a different bike, it rocks, it is the fastest accelerating quad out there!!!!!!!!!!!! :evilgrin

 

[xtremekv13]

try going up about 2 sizes with your pilot jet..mine still has a slight bog off idle but it is improved from falling on its face from idle..I am still messing with it just waiting for more jets to come in...and play with the air fuel screw[

 

[NHYFZ450]

Im at a #50 pilot jet with the screw 13/4 turns out, and it snaps to life with no hesitation what so ever.
Im also on the #5 clip position, and at a 172 main jet.

 

[LapTraffic]

Which Pilot Jets should I order?a 48 and a 50? Is this something a local shop will carry over the counter? How difficult is it to change?

 

[daddogrider]

not hard at all, here is a blowup of the carb so it can help you, print it out if it is ok with Yamaha.

http://www.eskimo.com/~daddog/repair/explodedcarb.jpg

they are kehin series #13 pilots and I would put in a 48 first.

 

[edgerat]

I am using a 45 at 200ft. It works great but I havent messed with anything richer yet.
Isaac

 

[LapTraffic]

Wow thanks for the IPB. That is exactly what I was looking for. I called Yamaha to see if it was ok to print. No freakin answer, so I guess Ill have to chance it

 

[WP]

Wow, I have not had mine on a dyno yet, but I had a 170 in mine with the timing mod, baffle removed, and lid off and it was too rich. I would land a jump and it would almost stall throwing me over the bars. People with aftermarket systems are using a 170. I used a 165 for now.

 

[yfzonly.com]

I'm at about 4,200 feet, what would you recommend. I know how to do plug burns, but I'm not sure where to start.

 

[LapTraffic]

Ok
Cam Timing Mod done (Super easy)
Baffle out of the pipe
Airbox lid off
170 main
Clip one up from the lowest position
50 pilot

All mods very easy to do and took no time even without a manual. That step by step walkthrough on the front was spot on.

So here's the deal. Im getting some rough running through the first 1/3 of the throtte get s worse the closer you get to the trasition from pilot to needle jetting. Very noticable if you hold it at a steady throttle at this point. Runs pretty rough, skippin and no rythym. Once you go above that it launches to life and boy howdy... HANG ON!

I cant imagine that Im too lean with a 50 pilot... I tried a 48 and got the same thing, too subtle if any change to note if it was getting better or worse. 42 pilot is stock.

Im going to go pick up some plugs to tune that way, and get a 46 pilot. If you have any suggestions please fire em my way.

Thanks!

 

[edgerat]

I am running the same mods but with the addition of a Sparks exhaust. I am at a
168 main
45 pilot
2 turns out on the fuel screw from bottomed
JD Jetting blue needle third clip

this thing is a monster and the hesitation is gone. The only thing you want to do is raise your idle, that will really help your engine to recover when you blip the throttle off idle.
Isaac

 

[LapTraffic]

Damn they were out of 45's at the shop.

So you think Im rich? I got 3 plugs to to do a plug check, but wont get to it till tomorrow. May put the stock 42 back in just to nail down a difference.

Onc eout of the pilot jet area it freakin screams. All the power you could want and them some

 

[Merriman®]

Well My deal witht he custom exhaust fell through, but I'm getting a sparks full next week. Right now With the cam mod, air box lid, and pea shooter taken out, I have a little hesitation on the bottom, but it fades out once you start riding. When my exhaust comes in I guess I'll be back to jetting..... :re