To Anyone With Aftermarket Exhaust...

I have a stock 07, 350 to 500 ft above sea level ( what is this for ) Just wondering what you would recommend for an exaust and filter upgrade, and whether i should take the lid off, just looking to get it running nice, might be out on a practice track every few weeks.

50 ft elevation, no lid, K&N, FMF 4.1 and power bomb, 50 pilot, 142 main, dynojet needle 5th clip, cam mod will be done sometime soon. so much bottem-end power my wheels spin for ever before they catch and get into a wheelie!

05 with a full titanum trinty exhaust 178 main 50 piolet retared 1 tooth and i belive the 2 from the bottom on the clip, and k&n no lid or box

fmf full exhaust with powderbomb header. 162 main, 45 pilot 1 3/4 turns out, 3rd clip ncvq needle

im so grateful to be in this forum.

Barker's exhaust
fci intake no box /cut 1 inch rat stack/ 42mm Carb/ cp 12;75.1 /venom port/stage 1 hc

220 4th ncvq 48 pilot

Right now I have a completely stock 2008. Im in Wisconsin at about 600 ft above sea level. I want to ride year round though which means cold winters!

I have a Yoshimura RS-2 Full exhaust sitting in the box on the garage floor. Thinking about running full exhaust with lid off for a while.

Suggestions on jetting? Will be doing zip tie mod when I jet. Thanks.

Didn't see this set up anywhere so here you go: full Barkers with k&n and outerwears w/ no lid. Riding at glamis so sea level and hot.
45
172
Ncvq 4th clip
2 1/2 on A/F screw
Just took it out for a test and the bike screams. Plug is a milky brown so I can't complain about this simple little setup

LRD Pro 4R full system
k&n Full intake system
480 big bore kit 13:1
@ 40° 1200'
48 pilot
ncvq needle 3rd notch
212 main jet
2 turns out air screw
r&d acc pump bowl all the way open

08 Motoworks slipon, K&N with prefilter, no lid, R&D Powerbowl with adj leak jet accel pump, 93 octane, ~250' elevation, Summer temps 80-100 - Winter temps 20-40

Main: 168 ran best so far bout to try a 165.. 170 lost a lot of low end and 2mph on top
Pilot: 45 upped it to 48 got rid of some of the popping on decel
GYTR needle: 4th clip
Fuel screw: 2 1/4 - 2 1/2
Leak jet set to around a 35

Still trying to get it spot on.

I have a 2012 YFZ and i have a k&n + modquad intake system and i am getting a slip on motoworks sr4g2 running between 50 ft. and almost 3000 feet when i go to the mountains what jetting size would you guys reccomend.

Just for reference I tried the Dynojet kit that MOtoworks suggested on their site. I tried both the Stage 2 settings from Dynojet and the settings Motoworks said and it wasn't nowhere near the power of the GYTR kit. Lost throughout the entire RPM range. However, I am having a strange throttle rising issue. At various speeds and at idle coming down from riding, the idle will rev up to about 1/4 throttle and stay that way. I can also turn the idle screw all the way out and the atv will not cut off. Tried playing with the throttle cable a little and didn't make a difference. No air leaks on boots around carb and none on exhaust. Slide isn't sticking either. But the jetting specs I listed before were the best results I could get so far. 80Mph and picks it up in 3rd.

great thread, saved me a lot of time!

alexasan27 said:

im so grateful to be in this forum.

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Me too

Ok new to this site... Have read several jetting posts... But can't get mine right. Just bought the quad last week...2004 yfz Supposedly has 14:1 compression , Mmad head work , cam mod, FCI , and it came with jardine exhaust. It ran kinda rough and the exhaust leaked. So I purchased a FULL DASA CLASSIC... Went to change the jets and noticed the Main was a 205 and the pilot a 40. I put in a 45 pj and the needle on the 4th , almost 2 turns out. The quad runs like a two stroke .... Bogs hard when at low RPM's and cuts out. But pop the clutch get some tire spin and she flys on WOT but just stabbing the throttle results in bog unless easing into it.. It also has zip tie mod at 2000 feet. Any suggestions?

04yfzSTROKED said:

Ok new to this site... Have read several jetting posts... But can't get mine right. Just bought the quad last week...2004 yfz Supposedly has 14:1 compression , Mmad head work , cam mod, FCI , and it came with jardine exhaust. It ran kinda rough and the exhaust leaked. So I purchased a FULL DASA CLASSIC... Went to change the jets and noticed the Main was a 205 and the pilot a 40. I put in a 45 pj and the needle on the 4th , almost 2 turns out. The quad runs like a two stroke .... Bogs hard when at low RPM's and cuts out. But pop the clutch get some tire spin and she flys on WOT but just stabbing the throttle results in bog unless easing into it.. It also has zip tie mod at 2000 feet. Any suggestions?

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205 main is HHHIIIIGGGHHHHHHHHH 175/180,( but make sure you're using Keihin jets, theres another type where the sizes are different.) should be plenty, 45p is good. Probably 3 clip from the bottom should be close. Double check the zip tie and make sure its still tight, and you can always go with a smaller leak jet. I had mine jetted too rich and it ran like poop. Super boggy and sputtered. So lean it out a bit and see what happens. Are you running straight Race fuel? Av-gas or vp110?

twistedmister said:

205 main is HHHIIIIGGGHHHHHHHHH 175/180,( but make sure you're using Keihin jets, theres another type where the sizes are different.) should be plenty, 45p is good. Probably 3 clip from the bottom should be close. Double check the zip tie and make sure its still tight, and you can always go with a smaller leak jet. I had mine jetted too rich and it ran like poop. Super boggy and sputtered. So lean it out a bit and see what happens. Are you running straight Race fuel? Av-gas or vp110?

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currently it has C12 in the tank. once thats out i will run just VP110 thats what my other bike runs... and i figured the 205 was high. i am running keihin jets. ill try adjusting the needle and putting a 180 Main jet. what size leak jet do you recommend?

redfrk22 said:

For those of you out there that are running modified stock pipes:

Drilled Pipe
No Baffle
GYTR Tip
K&N
No Lid
Cam Mod
Power Now W/Hole
600 ft, 75 deg

48 pilot, 172 main, Clip 3 on a NCVP Needle.

My plug is a little black but it runs good. Still fine tuning. :re

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What does the power now W/Hole.

great info here!