Fuel Petcock

Newbies, introduce yourself here. Are you thinking about getting one and have questions? Ask your basic questions here. Please post any tech questions in "The Order of The Greasy Wrench" section.
Forum rules
Here's the place for those who are newb or thinking about buying a Ural or Dnepr to introduce themselves ask those typical "newbie" questions. Try using the "Search" link at the top of the page to see if your question may have been asked before. Please post any tech questions in "The Order of the Greasy Wrench" section.
Post Reply
User avatar
Ragmanx1
Party Member
Party Member
Posts: 231
Joined: Mon Jul 13, 2015 3:44 pm
Location: Glide,Orygun

Fuel Petcock

Post by Ragmanx1 » Sat Jan 30, 2016 10:01 pm

Why do so many guys change out their stock fuel petcock for after market or other brand?

SteveG
2012 Ural Patrol

User avatar
Peter Pan
Order of Suvarov
Order of Suvarov
Posts: 3414
Joined: Fri Jan 31, 2014 11:30 pm
Location: Heredia, Costa Rica/screwing the heck out of the hack

Re: Fuel Petcock

Post by Peter Pan » Sat Jan 30, 2016 10:42 pm

or just modify it?
http://www.sovietsteeds.com/forums/view ... al#p405674

Simple>
If you have a IR temperature sensor gun you can see it by yourself...both cylinder head temparatures and exhaust temps are way off and on full throttle on a slope or with head wind your gasoline flow continues and will not start to starve.
As soon you have a manual petcock those issues become histories of the past.

Sven
Sophie Travelair = Patrol 2013
8 weeks 12.000km Oregon-Alaska-Oregon
With a DIY foam air filter the rig runs well even in tropical rain = :moto:
Final drives: 1. at 5000km, 2. at 34.000km(+friction plates) 3. at 42.386km
transmission: 1. 40.000km. 2. installed
Engine: 1. 43.388km crank replacement: Back on the road since 23.Okt.2019 :party:

The Avatar are 2 rice grains stating life's essence:
"The most important you cannot see!"
=> Attitude makes the difference!

User avatar
chaos2
Order of Suvarov
Order of Suvarov
Posts: 4966
Joined: Sun Apr 29, 2012 12:58 am
Location: sw ohio

Re: Fuel Petcock

Post by chaos2 » Sat Jan 30, 2016 10:55 pm

in other words, the stock petcock operates automatically via a vacuum line. If the line leaks it can cause the left cylinder to run lean and overheat. Or with the throttle wide open and reduced vacuum it may not flow enough gas. If the petcock malfunctions and the carb float valve leaks, the cylinder could fill with fuel leading to hydraulic lock and a bent crankshaft if you try to electric start it. The manual petcock is cheap and trouble free. Just have to remember to turn it on and off.
Last edited by chaos2 on Sat Jan 30, 2016 11:03 pm, edited 1 time in total.
past afflictions include limey motocars and bikes, R60/2, R65ls, and a Citroen.
Now an 87 K75s, DB Haanjo gravel bike, and a rusty 2012 GU bought new
dual K&N cones on homemade intake, 40/137.5
Raceway needles, Modtop exhaust
$29 VW Hydraulic steering dampener

User avatar
Albuquralque
Order of Victory
Order of Victory
Posts: 19677
Joined: Thu Jul 19, 2007 2:46 pm
Location: Albuquerque, NM

Re: Fuel Petcock

Post by Albuquralque » Sat Jan 30, 2016 10:57 pm

I've owned four Urals with the vacuum petcock and all four have failed. Meaning even with the engine off (no vacuum) the petcock allowed fuel to flow down to the carbs.
"Put a little gravel in your travel"


Previous Urals Owned: 2004 Wolf, 2006 Tourist, 2006 Patrol (TOW), 2006 Patrol (TOM), 2014 Patrol

User avatar
SidecarDan
Comrade General
Comrade General
Posts: 946
Joined: Thu Sep 20, 2012 10:18 am
Location: Abbotsford BC

Re: Fuel Petcock

Post by SidecarDan » Sat Jan 30, 2016 11:52 pm

I was having vacuum issues and was not getting enough gas to keep the right cylinder happy and was getting back firing and popping on the right. Changed to a Yamaha petcock and have not had any issues other than forgetting to turn it back on when I get on the bike.
Dan
2012 Forest Fog Gear-Up
128/42 jets
7/64ths drilled slides
2013 branch pipes
Yamaha petcock

stagewex
Hero of the Soviet Union - 2019
Hero of the Soviet Union - 2019
Posts: 6805
Joined: Sat Jul 14, 2012 10:45 pm
Location: New Rochelle, New York

Re: Fuel Petcock

Post by stagewex » Sun Jan 31, 2016 8:58 am

Albuquralque wrote:I've owned four Urals with the vacuum petcock and all four have failed. Meaning even with the engine off (no vacuum) the petcock allowed fuel to flow down to the carbs.
I have only had one (1) Ural over the last 9 years and still run the same original stock vacuum petcock. I have moved it 3 times from different types of fuel tanks. Have never had a problem except when I have left it on "PRI" because I'm an idiot. Same thing can happen with the Yamaha it you leave it "ON".

When and if it does fail I will probably change to the Yamaha. I guess I'm just so used to it and I don't like to mod things that already work. If yours has a problem them by all means change it.
Stagewex

Current Herd all running amok:
2008 Vespa 150S (Elec & Kick Start)
2007 Ural Patrol (2WD, Elec & Kick Start)
2006 Honda "Big Ruckus" PS250
2006 Yamaha TW200 (Elec & Kick Start)
1995 BMW K75 (Elec Start)
1991 Honda XR250L (Kick Start Only)
1986 Yamaha BW200ES (Elec & Kick Start)

User avatar
chaos2
Order of Suvarov
Order of Suvarov
Posts: 4966
Joined: Sun Apr 29, 2012 12:58 am
Location: sw ohio

Re: Fuel Petcock

Post by chaos2 » Sun Jan 31, 2016 11:38 am

after 25 years with a fuel injected bike and 2 years with the vacuum petcock it took a while for me to remember to turn the thing on an off. Fortunately my carb float valves never leaked and I always kick start the thing (flaky RPOS e-starter)
past afflictions include limey motocars and bikes, R60/2, R65ls, and a Citroen.
Now an 87 K75s, DB Haanjo gravel bike, and a rusty 2012 GU bought new
dual K&N cones on homemade intake, 40/137.5
Raceway needles, Modtop exhaust
$29 VW Hydraulic steering dampener

User avatar
Ragmanx1
Party Member
Party Member
Posts: 231
Joined: Mon Jul 13, 2015 3:44 pm
Location: Glide,Orygun

Re: Fuel Petcock

Post by Ragmanx1 » Mon Feb 01, 2016 8:12 pm

I bought a one on line for about $8 and free ship.
The stock one on my '12 Patrol works fine. I have a good fuel filter on both carbs and run non-ethanol gas.
I think I'll carry the replacement in my tool box. Pushing 71 years, I know I''ll forget to shut it off every time.
Kinda a catch 22 deal.
Thanx for all the help.
SteveG
2012 Ural Patrol

User avatar
harryball
Order of Lenin
Order of Lenin
Posts: 1573
Joined: Mon Oct 12, 2015 10:53 am
Location: Georgia
Contact:

Re: Fuel Petcock

Post by harryball » Wed Feb 03, 2016 10:46 pm

Here is my solution with the Yamaha 2GU-24500-02 which I got on Amazon for about $25 + $5 shipping. It was the last one for that supplier, looks like they are a few $$ more now but still not bad. I show what I had to do to modify it.

---
2017 - cT - "Georgia" My wife's rig.
2017 - M70/Retro, Sigmund. My wife's other rig.
Robert
http://HabitatForBats.org - Give a bat a home!

mouka
Comrade Colonel
Comrade Colonel
Posts: 302
Joined: Sun Jan 03, 2016 6:31 pm
Location: Naperville, Illinois

Re: Fuel Petcock

Post by mouka » Thu Feb 04, 2016 7:58 am

harryball wrote:Here is my solution with the Yamaha 2GU-24500-02 which I got on Amazon for about $25 + $5 shipping. It was the last one for that supplier, looks like they are a few $$ more now but still not bad. I show what I had to do to modify it.

Cheap Chinese knock offs sell for $8 shipped to your home. They work just as well as original Yamaha's.
2005 Honda Sabre 1100
2003 Ural Tourist
1998 Honda Aero 1100

User avatar
harryball
Order of Lenin
Order of Lenin
Posts: 1573
Joined: Mon Oct 12, 2015 10:53 am
Location: Georgia
Contact:

Re: Fuel Petcock

Post by harryball » Thu Feb 04, 2016 9:38 am

mouka wrote:Cheap Chinese knock offs sell for $8 shipped to your home. They work just as well as original Yamaha's.
My problem with "Cheap Chinese knock offs" is the components they use. They may work great out of the box... but what about a year from now? Try an experiment, go to a truck stop and purchase some black rubber bungees made in America. Then go find and buy some "identical" cheap Chinese knock offs. In about a year, or less, of use you will discover why the cheap ones are cheap. I'd rather not come back to find my fuel on the ground or in the cylinders when the rubber components disintegrate inside the petcock. Will that happen? I don't know, maybe they come from the same line and are just stolen from standard production and sold cheap, but there is not enough difference in price for me to want to take the chance.

My second problem is property and intellectual theft. I've been the victim of it, I do my best not to support it. There is a very good chance, like 101% chance, that those petcocks are a stolen reverse engineered design and a reasonable chance they are stolen property right off the Yamaha production line somewhere. That is why I asked, what part number is on the petcocks and there is none. Never stamped or ground off or ground off the molds.

You guys do what you want but I'm telling you, WATCH THEM CLOSELY, if they used cheap Chinese knock off rubber o-rings in those cheap Chinese knock off petcocks that $15 or so savings could be lost in one tank of fuel.
---
2017 - cT - "Georgia" My wife's rig.
2017 - M70/Retro, Sigmund. My wife's other rig.
Robert
http://HabitatForBats.org - Give a bat a home!

User avatar
Peter Pan
Order of Suvarov
Order of Suvarov
Posts: 3414
Joined: Fri Jan 31, 2014 11:30 pm
Location: Heredia, Costa Rica/screwing the heck out of the hack

Re: Fuel Petcock

Post by Peter Pan » Thu Feb 04, 2016 10:03 am

I had to smile about Harry's last comment...Story of my life too!
+1

By the way the manual petcock needs one thing. = do not become too lazy.
I am used to keep it all the time open.
My son Thomas experienced an interesting adventure yesterday... after a 1 1/2 hour ferry voyage...right cylinder was flooded and hydro locked.
Plus the right carb gave him interesting "insights" until the night.

Part of life and needed training for a future pilot.
Sven
Sophie Travelair = Patrol 2013
8 weeks 12.000km Oregon-Alaska-Oregon
With a DIY foam air filter the rig runs well even in tropical rain = :moto:
Final drives: 1. at 5000km, 2. at 34.000km(+friction plates) 3. at 42.386km
transmission: 1. 40.000km. 2. installed
Engine: 1. 43.388km crank replacement: Back on the road since 23.Okt.2019 :party:

The Avatar are 2 rice grains stating life's essence:
"The most important you cannot see!"
=> Attitude makes the difference!

User avatar
harryball
Order of Lenin
Order of Lenin
Posts: 1573
Joined: Mon Oct 12, 2015 10:53 am
Location: Georgia
Contact:

Re: Fuel Petcock

Post by harryball » Thu Feb 04, 2016 12:27 pm

Peter Pan wrote:I had to smile about Harry's last comment...Story of my life too!
+1

By the way the manual petcock needs one thing. = do not become too lazy.
I am used to keep it all the time open.
My son Thomas experienced an interesting adventure yesterday... after a 1 1/2 hour ferry voyage...right cylinder was flooded and hydro locked.
Plus the right carb gave him interesting "insights" until the night.

Part of life and needed training for a future pilot.
Sven
Yep, now that I have broken the habit of turning the petcock to "PRIME" when I get off due to my habit for turning it OFF... gotta rebuilt that habit and back it up as well. I was thinking about adding a decal on the dash/speedo "Fuel OFF?" or something to try and prompt me as a reminder.
---
2017 - cT - "Georgia" My wife's rig.
2017 - M70/Retro, Sigmund. My wife's other rig.
Robert
http://HabitatForBats.org - Give a bat a home!

User avatar
Peter Pan
Order of Suvarov
Order of Suvarov
Posts: 3414
Joined: Fri Jan 31, 2014 11:30 pm
Location: Heredia, Costa Rica/screwing the heck out of the hack

Re: Fuel Petcock

Post by Peter Pan » Thu Feb 04, 2016 10:26 pm

Not necessarily its needed to switch off on daily riding base. Just when you will leave her standing for long time or when she will get rocked. like on a trailer or ferry, then to lock off is a good habit.
I have the habit to keep the gasoline valve on most bikes continuously open for the last 30 years with the good result that the bowl needles are better seated. ...only trouble causers were NSU, MZ, Jawa.
Sophie Travelair = Patrol 2013
8 weeks 12.000km Oregon-Alaska-Oregon
With a DIY foam air filter the rig runs well even in tropical rain = :moto:
Final drives: 1. at 5000km, 2. at 34.000km(+friction plates) 3. at 42.386km
transmission: 1. 40.000km. 2. installed
Engine: 1. 43.388km crank replacement: Back on the road since 23.Okt.2019 :party:

The Avatar are 2 rice grains stating life's essence:
"The most important you cannot see!"
=> Attitude makes the difference!

User avatar
Ragmanx1
Party Member
Party Member
Posts: 231
Joined: Mon Jul 13, 2015 3:44 pm
Location: Glide,Orygun

Re: Fuel Petcock

Post by Ragmanx1 » Mon Feb 08, 2016 2:03 am

A fellow Comrade on the "Modifications" section found this vacuum petcock on Amazon. $6.90 with shipping.

http://www.amazon.com/gp/product/B008YC ... ages00#Ask

I also know if I get a simple (on/off/reserve) replacement I will forget to shut it off. :oops:

It looked good and ordered one. May be a good replacement or spare.

SteveG
2012 Ural Patrol

Post Reply