Jetting question???? - Yamaha YFZ450 Forum : YFZ450, YFZ450R, YFZ450X Forums

Coles_55 · 02-02-2012, 08:43 PM

Already searched and couldn't find a definitive answer on this. Running a full HMF exhause with a FCI at 1000-1500 ft. What jets should I run and how many turn out? If I missed it on my search please post...

**husker525** · 02-02-2012, 08:46 PM

Start with a 175 main jet, and a 45 pilot jet with an adjustable needle, probably on the 3rd to 4th clip down from the top, depending on if you have an NCVQ needle or just a stock adjustable needle on the 05. Go with 4th clip down from the top on the stock 05 needle, and 3rd down on an NCVQ. 2 turns out on the air/fuel screw.

Coles_55 · 02-02-2012, 09:31 PM

How do I know if I have an adjustable needle? I bought it stock like stock stock

Coles_55 · 02-03-2012, 05:40 PM

Is it worth buying a jet kit or just individual jets for this

**husker525** · 02-03-2012, 08:45 PM

I would stay away from buying a whole jet kit. Pull the needle out, and see if it has multiple clip settings. Jet kits have many jets that you will never need or use. It is cheaper just to buy individual jets. Often times, my dealership just give individual jets away, because everything is going to fuel injection. At last count at the end of 2011, we had over 15000 jets.

Coles_55 · 02-03-2012, 10:54 PM

I'm used to sleds so I will see how to take the needle out, and tomorrow I'm gonna stop by my stealership and she if he has jets in stock.

Coles_55 · 02-07-2012, 01:07 PM

Anyone has jets they wanna get rid of?

Coles_55 · 03-11-2012, 09:20 PM

Ok so I did all this and it's not running right at all. Idles pretty good but giving it any gas it wants to die. An occasional backfire and just seems like without the choke it barely even wants to idle. So what's wrong here?

soonerlightning · 03-11-2012, 10:16 PM

try a smaller main like a 162/165

seniortech · 03-11-2012, 11:00 PM

sounds like your starving for fuel. your cutting air while pulling the choke. your pilot jet may be to small.. do you know if there is any other work done ie. big bore porting

Coles_55 · 03-12-2012, 12:22 PM

No the motor is stock. Just running a FCI with open box, and a full hmf exhaust.

Coles_55 · 03-12-2012, 04:54 PM

Anyone?????

seniortech · 03-12-2012, 05:00 PM

Did you bye the bike used... Ie did someone try to do the cam mod and not know what the f they were doing sounds like your timing is off or your carb is like super clogged.... We need more input

Coles_55 · 03-12-2012, 07:47 PM

Yeah bought it used, guy didnt ride it for 3 years, and I highly doubt he would do a cam mod the bike was completely stock. I took the carb out and changed both jets 175 main and 45 pilot with 2 turns out. I will open the carb up again and check then in case they go dirty but I drained the tank right away to get all the old gas out. Also I noticed that if I run it with the petcock on ON its not getting fuel at all, so I cleaned the petcock filter and still nothing, now if I put it on RES the carb would get gas. Any ideas on that?? If you want me to I can take a video so you can hear exactly its doing....

seniortech · 03-12-2012, 07:54 PM

That would be great. Ps if your almost stock that 175 is way big... My bros yfz with fci , gytr pipe and cam mod runs best with a 160 main. Mine with a lot of work and ported head and carb and im at a 160 main and thats with vp113 fuel witch is highly oxygenated. Shot us a sound clip,, by the way my bro but a 180 main in thinking it was the 160 and it spit and sputtered like hell....

seniortech · 03-12-2012, 07:57 PM

You need to do the cam mod... You will not be disappointed... you might also be surprised at what you could find...

Coles_55 · 03-12-2012, 08:01 PM

Ok I will take a video real quick and post it somehow and hopefully that will help diagnose the problem. Any ideas on the fuel petcock??

seniortech · 03-12-2012, 08:08 PM

Yeah put in more fuel...lol Get a new one should be cheap...

Coles_55 · 03-12-2012, 08:19 PM

Well I got a video, let me know if this helps. The first part is when the choke is all the way out then it dies, the 2nd part is the choke all the way in.

Yfz450 - YouTube

seniortech · 03-12-2012, 08:32 PM

Man that thing sounds rough. no offense.. your way to fat or not getting any fuel at throttle, but there could be more to it... First you need the ziptie mod, second there is a throttle override on these bikes. its called t.o.r.s. There is a sensor on the carb and one on the thump throttle. They have to read together. When there is a problem in this system the bike thinks the carb is stuck open and shuts the ignition. You need to take the cover off the thump throttle and see if the plungger is moving freely.. Go on youtube and look up or google how to bypass this system.. It is very easy, but if it works i DONT recomend leaving it that way... Fix it. Even being fat it sould still rev better than that.. Did you clean the needle and seat in the carb bowl when you cleaned it. Open the carb bowl drain its like a 3 or 4mm alen head screw and see if plenty of fuel flows out. Also check the needle. The clip may have fallen off. Get back to me....

02-02-2012, 08:43 PM	#1 (permalink)
Coles_55 Senior Member Join Date: Jan 2012 Location: Eagle Wi Posts: 138	Jetting question???? Already searched and couldn't find a definitive answer on this. Running a full HMF exhause with a FCI at 1000-1500 ft. What jets should I run and how many turn out? If I missed it on my search please post... __________________ 2005 YFZ450 - WestCoast Red Nerfs, HMF Red Full Exhaust, Fuel Customs Intake, Fly Handlebars w/ Fly Bar Pad. More to come!

02-02-2012, 08:46 PM	#2 (permalink)
husker525 Police Patrol Join Date: Sep 2005 Location: Parker, Colorado Posts: 3,118	Start with a 175 main jet, and a 45 pilot jet with an adjustable needle, probably on the 3rd to 4th clip down from the top, depending on if you have an NCVQ needle or just a stock adjustable needle on the 05. Go with 4th clip down from the top on the stock 05 needle, and 3rd down on an NCVQ. 2 turns out on the air/fuel screw. __________________ TEAM TRIGGER RACING (Now sponsored by AMSOIL, Vickery Motorsports, MotoXNutrition,DZ Graphics, Engine Ice, DeRisi Racing, Team Ape, Cosworth Pistons, Hiper, Lonestar Racing. Terse 07 Race engine 2007 Blue YFZ: Venom 14:1 piston, Cam Mod, Jardine RT4 Exhaust, 175 main, 45 pilot, 04 needle 3rd clip/ 3 t Become a fan of Team Trigger Racing on Facebook!!!

02-02-2012, 09:31 PM	#3 (permalink)
Coles_55 Senior Member Join Date: Jan 2012 Location: Eagle Wi Posts: 138	How do I know if I have an adjustable needle? I bought it stock like stock stock __________________ 2005 YFZ450 - WestCoast Red Nerfs, HMF Red Full Exhaust, Fuel Customs Intake, Fly Handlebars w/ Fly Bar Pad. More to come!

02-03-2012, 05:40 PM	#4 (permalink)
Coles_55 Senior Member Join Date: Jan 2012 Location: Eagle Wi Posts: 138	Is it worth buying a jet kit or just individual jets for this __________________ 2005 YFZ450 - WestCoast Red Nerfs, HMF Red Full Exhaust, Fuel Customs Intake, Fly Handlebars w/ Fly Bar Pad. More to come!

02-03-2012, 08:45 PM	#5 (permalink)
husker525 Police Patrol Join Date: Sep 2005 Location: Parker, Colorado Posts: 3,118	I would stay away from buying a whole jet kit. Pull the needle out, and see if it has multiple clip settings. Jet kits have many jets that you will never need or use. It is cheaper just to buy individual jets. Often times, my dealership just give individual jets away, because everything is going to fuel injection. At last count at the end of 2011, we had over 15000 jets. __________________ TEAM TRIGGER RACING (Now sponsored by AMSOIL, Vickery Motorsports, MotoXNutrition,DZ Graphics, Engine Ice, DeRisi Racing, Team Ape, Cosworth Pistons, Hiper, Lonestar Racing. Terse 07 Race engine 2007 Blue YFZ: Venom 14:1 piston, Cam Mod, Jardine RT4 Exhaust, 175 main, 45 pilot, 04 needle 3rd clip/ 3 t Become a fan of Team Trigger Racing on Facebook!!!

02-03-2012, 10:54 PM	#6 (permalink)
Coles_55 Senior Member Join Date: Jan 2012 Location: Eagle Wi Posts: 138	I'm used to sleds so I will see how to take the needle out, and tomorrow I'm gonna stop by my stealership and she if he has jets in stock. __________________ 2005 YFZ450 - WestCoast Red Nerfs, HMF Red Full Exhaust, Fuel Customs Intake, Fly Handlebars w/ Fly Bar Pad. More to come!

02-07-2012, 01:07 PM	#7 (permalink)
Coles_55 Senior Member Join Date: Jan 2012 Location: Eagle Wi Posts: 138	Anyone has jets they wanna get rid of? __________________ 2005 YFZ450 - WestCoast Red Nerfs, HMF Red Full Exhaust, Fuel Customs Intake, Fly Handlebars w/ Fly Bar Pad. More to come!

03-11-2012, 09:20 PM	#8 (permalink)
Coles_55 Senior Member Join Date: Jan 2012 Location: Eagle Wi Posts: 138	Ok so I did all this and it's not running right at all. Idles pretty good but giving it any gas it wants to die. An occasional backfire and just seems like without the choke it barely even wants to idle. So what's wrong here? __________________ 2005 YFZ450 - WestCoast Red Nerfs, HMF Red Full Exhaust, Fuel Customs Intake, Fly Handlebars w/ Fly Bar Pad. More to come!

03-11-2012, 10:16 PM	#9 (permalink)
soonerlightning Senior Member Join Date: Oct 2003 Posts: 194	try a smaller main like a 162/165

03-11-2012, 11:00 PM	#10 (permalink)
seniortech Senior Member Join Date: Mar 2012 Location: Charleston, South Carolina Posts: 1,355	sounds like your starving for fuel. your cutting air while pulling the choke. your pilot jet may be to small.. do you know if there is any other work done ie. big bore porting

03-12-2012, 12:22 PM	#11 (permalink)
Coles_55 Senior Member Join Date: Jan 2012 Location: Eagle Wi Posts: 138	No the motor is stock. Just running a FCI with open box, and a full hmf exhaust. __________________ 2005 YFZ450 - WestCoast Red Nerfs, HMF Red Full Exhaust, Fuel Customs Intake, Fly Handlebars w/ Fly Bar Pad. More to come! Last edited by Coles_55; 03-12-2012 at 12:44 PM.

03-12-2012, 04:54 PM	#12 (permalink)
Coles_55 Senior Member Join Date: Jan 2012 Location: Eagle Wi Posts: 138	Anyone????? __________________ 2005 YFZ450 - WestCoast Red Nerfs, HMF Red Full Exhaust, Fuel Customs Intake, Fly Handlebars w/ Fly Bar Pad. More to come!

03-12-2012, 05:00 PM	#13 (permalink)
seniortech Senior Member Join Date: Mar 2012 Location: Charleston, South Carolina Posts: 1,355	Did you bye the bike used... Ie did someone try to do the cam mod and not know what the f they were doing sounds like your timing is off or your carb is like super clogged.... We need more input

03-12-2012, 07:47 PM	#14 (permalink)
Coles_55 Senior Member Join Date: Jan 2012 Location: Eagle Wi Posts: 138	Yeah bought it used, guy didnt ride it for 3 years, and I highly doubt he would do a cam mod the bike was completely stock. I took the carb out and changed both jets 175 main and 45 pilot with 2 turns out. I will open the carb up again and check then in case they go dirty but I drained the tank right away to get all the old gas out. Also I noticed that if I run it with the petcock on ON its not getting fuel at all, so I cleaned the petcock filter and still nothing, now if I put it on RES the carb would get gas. Any ideas on that?? If you want me to I can take a video so you can hear exactly its doing.... __________________ 2005 YFZ450 - WestCoast Red Nerfs, HMF Red Full Exhaust, Fuel Customs Intake, Fly Handlebars w/ Fly Bar Pad. More to come!

03-12-2012, 07:54 PM	#15 (permalink)
seniortech Senior Member Join Date: Mar 2012 Location: Charleston, South Carolina Posts: 1,355	That would be great. Ps if your almost stock that 175 is way big... My bros yfz with fci , gytr pipe and cam mod runs best with a 160 main. Mine with a lot of work and ported head and carb and im at a 160 main and thats with vp113 fuel witch is highly oxygenated. Shot us a sound clip,, by the way my bro but a 180 main in thinking it was the 160 and it spit and sputtered like hell....

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03-12-2012, 07:57 PM	#16 (permalink)
seniortech Senior Member Join Date: Mar 2012 Location: Charleston, South Carolina Posts: 1,355	You need to do the cam mod... You will not be disappointed... you might also be surprised at what you could find...

03-12-2012, 08:01 PM	#17 (permalink)
Coles_55 Senior Member Join Date: Jan 2012 Location: Eagle Wi Posts: 138	Ok I will take a video real quick and post it somehow and hopefully that will help diagnose the problem. Any ideas on the fuel petcock?? __________________ 2005 YFZ450 - WestCoast Red Nerfs, HMF Red Full Exhaust, Fuel Customs Intake, Fly Handlebars w/ Fly Bar Pad. More to come!

03-12-2012, 08:08 PM	#18 (permalink)
seniortech Senior Member Join Date: Mar 2012 Location: Charleston, South Carolina Posts: 1,355	Yeah put in more fuel...lol Get a new one should be cheap...

03-12-2012, 08:19 PM	#19 (permalink)
Coles_55 Senior Member Join Date: Jan 2012 Location: Eagle Wi Posts: 138	Well I got a video, let me know if this helps. The first part is when the choke is all the way out then it dies, the 2nd part is the choke all the way in. Yfz450 - YouTube __________________ 2005 YFZ450 - WestCoast Red Nerfs, HMF Red Full Exhaust, Fuel Customs Intake, Fly Handlebars w/ Fly Bar Pad. More to come!

03-12-2012, 08:32 PM	#20 (permalink)
seniortech Senior Member Join Date: Mar 2012 Location: Charleston, South Carolina Posts: 1,355	Man that thing sounds rough. no offense.. your way to fat or not getting any fuel at throttle, but there could be more to it... First you need the ziptie mod, second there is a throttle override on these bikes. its called t.o.r.s. There is a sensor on the carb and one on the thump throttle. They have to read together. When there is a problem in this system the bike thinks the carb is stuck open and shuts the ignition. You need to take the cover off the thump throttle and see if the plungger is moving freely.. Go on youtube and look up or google how to bypass this system.. It is very easy, but if it works i DONT recomend leaving it that way... Fix it. Even being fat it sould still rev better than that.. Did you clean the needle and seat in the carb bowl when you cleaned it. Open the carb bowl drain its like a 3 or 4mm alen head screw and see if plenty of fuel flows out. Also check the needle. The clip may have fallen off. Get back to me....