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Quick question (fuel petcock)

Started by FJdude, May 15, 2012, 09:52:52 AM

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FJdude

May 15, 2012, 09:52:52 AM
Which way is the fuel petcock supposed to be pointed; left/right or up/down???

Have an 86 or 87 Fj1200.

moparman70

#1
May 15, 2012, 10:57:59 AM
If its original the 86-87 doesn't have a manual petcock - its done by vacuum -- and has a electronic type reserve ( not going into detail here about how that works -- do a search if you want too)

no access to the petcock on this model or any model that I know of

     

FJdude

#2
May 15, 2012, 02:40:55 PM
It has the electronic switch for the reserve but there's also a petcock on the tank. The petcock has two positions; one which will flow gas freely, and the other which doesn't. So I'm unsure if the one that doesn't is the off or if it is suction because the bike won't run for more then a few miles when on that setting. So I have resorted to turn the petcock to where gas flows out freely, I just would like to know what the two settings are...

Pat Conlon

#3
May 15, 2012, 03:37:49 PM
2 settings:
1) Prime, where the gas flows freely...as in to "prime" your carbs.
2) ON,  is the normal setting which when the vacuum  is present the petcock opens up and gas flows.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

FJdude

#4
May 15, 2012, 06:04:21 PM
Quote from: Pat Conlon on May 15, 2012, 03:37:49 PM
2 settings:
1) Prime, where the gas flows freely...as in to "prime" your carbs.
2) ON,  is the normal setting which when the vacuum  is present the petcock opens up and gas flows.

Okay. So I'm guessing the vacuum doesn't work because the bike will only run on the "prime" setting. I'll try replacing the vacuum tube, but what are some other steps I should take to fix this problem???

Thank you

P.S. can I ride the bike on the prime setting???

Pat Conlon

#5
May 15, 2012, 08:24:36 PM
Don't leave your bike with the petcock on prime. There are many things that can go wrong.
All you need is a small piece of dirt between the float needle and seat and you will....
Spill a LOT of gas on your garage floor....
Fill up your cylinders with gas....
Fill up your crankcase with gas....
Thumb the starter with a cylinder full of gas and you will experience a wonderful event called hydro locking.

And you think you have problems now... :bomb: Consider yourself warned.

With the petcock in the "on" position, put a hose on the vacuum port on the petcock and suck.... The petcock should open....if not buy a new petcock.
If it does open, your petcock is good and you now have to figure out why the petcock is not getting a vacuum signal.... Simple.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

FJmonkey

#6
May 15, 2012, 08:35:02 PM
Quote from: Pat Conlon on May 15, 2012, 08:24:36 PM
With the petcock in the "on" position, put a hose on the vacuum port on the petcock and suck.... The petcock should open....if not buy a new petcock.
If it does open, your petcock is good and you now have to figure out why the petcock is not getting a vacuum signal.... Simple.
I can't help myself... Sucking on your petcock can save your FJ???  :lol: :lol: :lol: :lol: :lol:

As you were gents, just having a juvenile moment....
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

Pat Conlon

#7
May 15, 2012, 08:44:41 PM
Mark, Mark....Mark. (that was funny) :good2:
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

moparman70

#8
May 15, 2012, 11:37:10 PM
well, just for my clarification if you do have a petcock that you can switch to PRIME and ON then it is not the original petcock that came with an 86 or 87 --- I am looking at my spare and there is no moving parts.  Can you take a picture of this thing as you may not have an original petcock.

As far as the original one goes -- vacuum opens it up and closes it.  Search for answers on this as its been asked and answered.  Send us a photo of what you got because its sounds different.



     

SlowOldGuy

#9
May 16, 2012, 11:05:36 AM
If there's no wires on it then I think he's got an '84/'85 petcock.

DavidR.

Pat Conlon

#10
May 16, 2012, 12:29:07 PM
One of the many, many reasons the '84/85's are superior....... (popcorn)
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

craigo

#11
May 16, 2012, 04:04:51 PM
Quote from: Pat Conlon on May 16, 2012, 12:29:07 PM
One of the many, many reasons the '84/85's are superior....... (popcorn)

No they aren't  (popcorn) :bomb: :biggrin:

CraigO
CraigO
90FJ1200

racerrad8

#12
May 17, 2012, 01:20:11 AM
Both petcocks are listed at www.RPMracingCa.com

You can see the difference between the two to determine what exactly you have.

Randy - RPM
Randy - RPM

FJdude

#13
May 17, 2012, 11:31:46 AM
Yup it looks like it is the 84-85 petcockguezs I need tO check my registration and see what year my bike really is...

Anyways I took the petcock off and apart last night to see if the gaskets were still good and nothing was clogged. I put suction on the vacuum tube and sucked on the fuel line and air was coming out so the vacuum was working. I'll take it out for another ride and see if she dies again...and if it does I don't know where to go from there
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