This Is How To Bypass The Vacuum Fuel Line

MYZ400 · 02-19-2007, 01:40 AM

I read a post ( Fuel Off Valve ) by SRchop16 concerning the stock fuel valves on the Z400. In that post, NormalZ gave a link ( Bypass the vacuum fuel valve ) to another helpful post. I have a 2006 Z400 and a couple people towards the end of the post advised that this procedure doesn't work on 2006 models. I have had problems with my 2006 stock petcock and I wanted to thank all of you that helped out. I decided to take my petcock off to clean it and look for a way to make the mod work on 2006 models. I was able to come up with a solution to the problem. The mod is as follows.....

1- Remove the entire petcock from the gas tank.

2- Remove the "vacuum line cover" from the back of the petcock. Be careful, there's a spring inside

3- Pull out the "vacuum line plug" being careful not to damage the square rubber gasket (disregard the yellow circle in the picture)

4- Cut around the "vacuum line plug" to remove the square rubber gasket. You should have something that looks like this.

5- Keep the square rubber gasket and set aside the "vacuum line plug" and the "vacuum line spring", these won't be reinstalled.

6- Plug the small hole on the inside of the "vacuum line cover" and the exterior "vacuum line tube" to stop gas from leaking in to the vent line. Before I pluged the inside small hole......

After the plug.....

I used this stuff from Advance Auto Parts called "Quick Steel" ($4.68). It's an epoxy that sets up in 1 hour and is impervious to chemicals.

7- After the plugs that you made are dry, reassemble the "vacuum line cover" with the square rubber gasket. Don't reinstall the spring or the "vacuum line plug" that was cut off of the square rubber gasket.

8- Vacuum is no longer needed on any position on the fuel valve. The "on", "reserve" and "prime" positions are all free flowing now. Keep in mind that running with the fuel switch in the "prime" position is just like running in the "reserve" position.

9- After completing this mod, you will no longer have an "off" position. To solve this, I purchased an in-line fuel shut off valve from Tractor Supply ($6.94). It's made by Briggs and Stratton (part# 5091). To shut off all fuel flow to the carb, I simply turn this in-line valve to off.

valve open....

valve closed...

I also hooked the rubber vacuum line back up to the back of the petcock and carb just to keep junk out of the carb. I also installed an in-line fuel filter and Tusk gas cap while I was at it.

Please excuse my dirty ride. I had to test this mod out. I have no leaks and no more vacuum problems. My ride runs good again.... and now I have "on", "reserve" and a real "off" position.

suzuki88 · 02-19-2007, 07:02 AM

Great write up but for all your work and the money it cost you you could of got a new petcock for 20 bucks.I read that a raptor-660 works.I used an old petcock off an old oversized kawi tank that I have.

MYZ400 · 02-20-2007, 01:48 AM

It takes about a half hour to do the mod (not including the dry time) and costs $12. Went to McDonald's with all the money I saved.

NormalZ · 02-20-2007, 12:33 PM

Pinned... Good write-up, explanations, and pics. Good job!

drzoo2 · 02-20-2007, 12:35 PM

Other than the loss of reserve, what other advantage is there to just running on prime?

z

flynbryan · 02-20-2007, 01:33 PM

Some find that the fuel flow in the "ON" position is inadequate or inconsistent. Running it on "Prime" is the same as "on" on a standard petcock.

mmikulak · 02-20-2007, 09:16 PM

QUOTE (drzoo2 @ Feb 20 2007, 10:35 AM)

Quote:

Other than the loss of reserve, what other advantage is there to just running on prime?

z[/b]

You have to run on prime if you get the FCR carb. Most popular carb option.

CFM-Z440 · 02-20-2007, 10:19 PM

I havent tried it (yet) but I have heard that a 660 raptor fuel petcock will fit it.

06DVX400 · 02-23-2007, 08:18 PM

i have a stock carb and i noticed my bike runs like sht on the ON part, doesnt get enough fuel...i just turn it on PRI and it hasnt failed yet....

in the manuel it says to never leave the bike on the PRI position when not running, i've forgot to put it back in the ON position a couple times and left it for about a week and nothing has happened, bike started up fine...

is leaving it on PRI actually that harmful to my quad?

CFM-Z440 · 02-23-2007, 09:00 PM

QUOTE (06DVX400 @ Feb 23 2007, 08:18 PM)

Quote:

i have a stock carb and i noticed my bike runs like sht on the ON part, doesnt get enough fuel...i just turn it on PRI and it hasnt failed yet....
in the manuel it says to never leave the bike on the PRI position when not running, i've forgot to put it back in the ON position a couple times and left it for about a week and nothing has happened, bike started up fine...
is leaving it on PRI actually that harmful to my quad?[/b]

If the needle valve is good in your carburetor, then you will never have a problem with the pri position.
Pri is reserve that does not shut off when the engine does. It is manual reserve.

mrgixxer6 · 03-02-2007, 09:32 PM

so what is the real benefit to this mod?? just curious. thanks
dave

ponycar_troy · 06-06-2007, 06:16 PM

QUOTE (mrgixxer6 @ Mar 2 2007, 08:32 PM)

Quote:

so what is the real benefit to this mod?? just curious. thanks
dave[/b]

running in the prime is just like running in reserve so when your out there is nothing left but if you mod it you can run an fcr carb in the on position and still have the reserve so you dont have to walk back to the truck to get your gas can. and trust me i've had to do it and it sucks.

drnez · 09-05-2007, 04:34 PM

Search, there are several folks on here who use raptor petcocks.

bludevilz91 · 01-15-2008, 06:25 PM

I had a problem with the raptor petcock. The selector was rightup against the frame so I couldn't turn it. I just did a mod similiar to this and plugged off the vacuum hole. I run the FCR thats why I had to do this.

Do Work! · 07-31-2008, 01:33 PM

MYZ, what kind of problems were you having with your 06 and the petcock?? I have a 06, and it doesn't seem to want to start. I'm interested in knowing what your problems were......

Thanks!

02-19-2007, 01:40 AM	#1 (permalink)
MYZ400 :::Mini LT80 Rider::: Join Date: Jan 2007 Location: Trenton, Ohio Posts: 255	I read a post ( Fuel Off Valve ) by SRchop16 concerning the stock fuel valves on the Z400. In that post, NormalZ gave a link ( Bypass the vacuum fuel valve ) to another helpful post. I have a 2006 Z400 and a couple people towards the end of the post advised that this procedure doesn't work on 2006 models. I have had problems with my 2006 stock petcock and I wanted to thank all of you that helped out. I decided to take my petcock off to clean it and look for a way to make the mod work on 2006 models. I was able to come up with a solution to the problem. The mod is as follows..... 1- Remove the entire petcock from the gas tank. 2- Remove the "vacuum line cover" from the back of the petcock. Be careful, there's a spring inside 3- Pull out the "vacuum line plug" being careful not to damage the square rubber gasket (disregard the yellow circle in the picture) 4- Cut around the "vacuum line plug" to remove the square rubber gasket. You should have something that looks like this. 5- Keep the square rubber gasket and set aside the "vacuum line plug" and the "vacuum line spring", these won't be reinstalled. 6- Plug the small hole on the inside of the "vacuum line cover" and the exterior "vacuum line tube" to stop gas from leaking in to the vent line. Before I pluged the inside small hole...... After the plug..... I used this stuff from Advance Auto Parts called "Quick Steel" ($4.68). It's an epoxy that sets up in 1 hour and is impervious to chemicals. 7- After the plugs that you made are dry, reassemble the "vacuum line cover" with the square rubber gasket. Don't reinstall the spring or the "vacuum line plug" that was cut off of the square rubber gasket. 8- Vacuum is no longer needed on any position on the fuel valve. The "on", "reserve" and "prime" positions are all free flowing now. Keep in mind that running with the fuel switch in the "prime" position is just like running in the "reserve" position. 9- After completing this mod, you will no longer have an "off" position. To solve this, I purchased an in-line fuel shut off valve from Tractor Supply ($6.94). It's made by Briggs and Stratton (part# 5091). To shut off all fuel flow to the carb, I simply turn this in-line valve to off. valve open.... valve closed... I also hooked the rubber vacuum line back up to the back of the petcock and carb just to keep junk out of the carb. I also installed an in-line fuel filter and Tusk gas cap while I was at it. Please excuse my dirty ride. I had to test this mod out. I have no leaks and no more vacuum problems. My ride runs good again.... and now I have "on", "reserve" and a real "off" position. __________________ 2006 LTZ400 PERFORMANCE 13 tooth front sprocket; pull choke; petcock mod; clamp on K&N air filter with outerwear and lid removed; removed screen from intake tube; Yoshimura RS-3 Full Exhaust; Dyno-Jet kit currently running a 160 main/needle-3rd clip/25 pilot/fuel screw 2.25 out/elevation 650 ft; Motion Pro Terminator clutch cable. REINFORCEMENTS Tusk nerf bars; Tusk Typhoon rear rotor; Tusk billet gas cap; Tusk parking brake block off; G-Force axle; Armadillo full skid plate; Armadillo A-arm guards; Armadillo swing arm guard; Pro Armor link guard; Pro Armor Dominator bumper; Fuel ATV cooler rack; Pro Design case saver; PowerMadd hand guards; front & rear shock covers; Works Connection frame guards; Garmin Etrex GPS; Hard Looks custom warning labels; IMS 4 gallon fuel tank; Stainless steel rear brake line.

02-20-2007, 01:48 AM	#3 (permalink)
MYZ400 :::Mini LT80 Rider::: Join Date: Jan 2007 Location: Trenton, Ohio Posts: 255	It takes about a half hour to do the mod (not including the dry time) and costs $12. Went to McDonald's with all the money I saved. __________________ 2006 LTZ400 PERFORMANCE 13 tooth front sprocket; pull choke; petcock mod; clamp on K&N air filter with outerwear and lid removed; removed screen from intake tube; Yoshimura RS-3 Full Exhaust; Dyno-Jet kit currently running a 160 main/needle-3rd clip/25 pilot/fuel screw 2.25 out/elevation 650 ft; Motion Pro Terminator clutch cable. REINFORCEMENTS Tusk nerf bars; Tusk Typhoon rear rotor; Tusk billet gas cap; Tusk parking brake block off; G-Force axle; Armadillo full skid plate; Armadillo A-arm guards; Armadillo swing arm guard; Pro Armor link guard; Pro Armor Dominator bumper; Fuel ATV cooler rack; Pro Design case saver; PowerMadd hand guards; front & rear shock covers; Works Connection frame guards; Garmin Etrex GPS; Hard Looks custom warning labels; IMS 4 gallon fuel tank; Stainless steel rear brake line.

02-20-2007, 12:33 PM	#4 (permalink)
NormalZ Administrator Join Date: Sep 2003 Location: Southern Arizona for awhile... Posts: 10,396	Pinned... Good write-up, explanations, and pics. Good job! __________________ July 2005 QOTM

02-20-2007, 12:35 PM	#5 (permalink)
drzoo2 :::LT500 Rider::: Join Date: Jun 2006 Location: STNY Posts: 1,079	Other than the loss of reserve, what other advantage is there to just running on prime? z __________________ '06 Yellow LTZ400 Full FMF Ti-4 system, K&N Filter and Power lid and NS Hotcams Stock Carb, 155 main, 25 pilot, 2.25 turns Fuel screw, Alba Needle 3rd Clip. Elevation 1400' EX DG nerfs modded to fit, Team Zuki Heel Guards, AC Bumper Renthol Banshee Bend Bars, One Indutries Graphics LSR Front Spindles and +2 +4 Rear Axle with Holeshot HD's Custom Warning labels and Dash

02-20-2007, 01:33 PM	#6 (permalink)
flynbryan :::LT500 Rider::: Join Date: Nov 2005 Posts: 1,113	Some find that the fuel flow in the "ON" position is inadequate or inconsistent. Running it on "Prime" is the same as "on" on a standard petcock. __________________ 07' Trx450er Thanks to my 2010' season sponsors/supporters CV4 BNR Motorsports GBC Motorsports GT Thunder Spider Grips Scott USA Powermadd "I can do all things through Christ Jesus who strengthens me"

02-19-2007, 07:02 AM	#2 (permalink)
suzuki88 :::Mini LT50 Rider::: Join Date: Dec 2006 Posts: 83	Great write up but for all your work and the money it cost you you could of got a new petcock for 20 bucks.I read that a raptor-660 works.I used an old petcock off an old oversized kawi tank that I have.

02-20-2007, 10:19 PM	#8 (permalink)
CFM-Z440 Super Moderator Join Date: Sep 2006 Location: Southern Minnesota Posts: 6,437	I havent tried it (yet) but I have heard that a 660 raptor fuel petcock will fit it. __________________ 03 LT-Z 470 Max Power 12.5:1 94mm Piston, Hot Rods +5 Stroker Crank, Web Cams 539 (+6) IN / 539 EX, with Hot Cams sprockets, Ferrea +1 Valves, LTZ/DRZ springs (IN)DRZ springs (EX), DRZ Manual Decomp. Ported head, FCR 41 with Noss adaptor, Home made intake, Modified HMF Full System, Home made header, Trailtech flywheel, Dyna Programable 54hp 36ft lbs

02-23-2007, 08:18 PM	#9 (permalink)
06DVX400 :::Mini LT80 Rider::: Join Date: Jan 2007 Posts: 201	i have a stock carb and i noticed my bike runs like sht on the ON part, doesnt get enough fuel...i just turn it on PRI and it hasnt failed yet.... in the manuel it says to never leave the bike on the PRI position when not running, i've forgot to put it back in the ON position a couple times and left it for about a week and nothing has happened, bike started up fine... is leaving it on PRI actually that harmful to my quad? __________________ 2006 DVX400 Tony Stewart edition Big Gun full exhaust kn air filter dynojet kit Main 160, pilot stock, needle 3rd clip, fuel screw 1.5 turns out arctic cat nerf bars and hand guards snorkel off, air box lid on

03-02-2007, 09:32 PM	#11 (permalink)
mrgixxer6 :::Z400 Rider::: Join Date: Sep 2006 Location: Pennsdale, PA Posts: 886	so what is the real benefit to this mod?? just curious. thanks dave __________________ Luke's Racing 450cc - 39mm FCR (178MJ, 55PJ, NCVQ 3rd Clip, Zip-Ty 1.25turns) - Boyesen QuickShot - CFM Aluminum Airbox w/Dual Stage UNI - 400EX Intake Boot - HotCams In/Ex - Kibblewhite In/Ex Valves - Kibblewhite Spring Kit - Dynatek CDI - FMF PowerCore 4 w/Powerbomb System - LSR Spindles - JT Sprockets (15t/39t) - RK X-Ring Chain - Moose Billet Case Saver - 2005 KFX Front Shocks - Denton 7-Way Damper - OMF Radiator Scoops - Pro Armor Nerfs with Fat Pegs - Pro Armor BullHorn - Pro Armor Pro Race Grab Bar - ITP Holeshot GNCC's on Black T-9's - Armadillo Chassis, Swing Arm, Rear Shock and A-Arm Skids - Fly Aero Flex Bars (Banshee Bend) - MSR AOF Clutch LVR w/Hotstart for Reverse - UFO HandguardsCheck Out My Myspace!!!

09-05-2007, 04:34 PM	#13 (permalink)
drnez :::Official Spammer::: Join Date: Jan 2006 Location: Atlanta, GA Posts: 4,941	Search, there are several folks on here who use raptor petcocks. __________________ Building another KFX. Let the money pit begin!

01-15-2008, 06:25 PM	#14 (permalink)
bludevilz91 :::Ozark 250 rider::: Join Date: Sep 2006 Posts: 357	I had a problem with the raptor petcock. The selector was rightup against the frame so I couldn't turn it. I just did a mod similiar to this and plugged off the vacuum hole. I run the FCR thats why I had to do this. __________________ YOSHIMURA RS-3 STAINLESS STEEL FULL SYSTEM ATHENA 434 OLD STYLE HOT CAMS, FERREA STAINLESS STEEL VALVES, KIBBLEWHITE VALVE SPRINGS PRO DESIGN K&N W/ OUTERWEARS AND CUSTOM LID AND 400EX AIR TUBE FCR 40 OFF OF CRF450: 172 MAIN JET, 45 PILOT, 1.5 TURNS, 35 LEAK JET, NEEDLE ON 2ND CLIP FROM TOP RAZR 2's ON .190's IN THE REAR AND RAZR's ON .190's UP FRONT BLACK MAIERS WITH BOMBSQUAD GRAPHICS 13/40 JT SPROCKET GEARING ARMADILLO AND PRO-ARMOR UNDERSIDE

07-31-2008, 01:33 PM	#15 (permalink)
Do Work! :::Rookie Rider::: Join Date: Jul 2008 Location: T-Roy, OH Posts: 10	MYZ, what kind of problems were you having with your 06 and the petcock?? I have a 06, and it doesn't seem to want to start. I'm interested in knowing what your problems were...... Thanks! __________________ http://vids.myspace.com/index.cfm?fuseacti...ideoid=36781313 Short vid of my Z... Full HMF Sport Series 170MJ K&N Air Filter Intake screen removed AMR Monster Coil HolesShots on the rear. Denton rebuildable steering stabilizer. R-660 petcock on the tank!! FCR 39mm soon........ Ignition coming soon..... Any recommendations......

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