I recently needed to drain the fuel tank on my 86 FJ so i hooked a hand held vacuum pump to the petcock and found it would not hold vacuum. The petcock worked as long as i kept pumping but would leak down as soon as i stopped. I replaced this petcock about ten years ago so i was not expecting it to be bad again. I bought a rebuild kit from RPM but it made no difference. Is there something else i need to do when testing it other than just the vacuum pump? Any help would be greatly appreciated.
Quote from: pwhitacre on July 28, 2020, 09:08:21 PMI recently needed to drain the fuel tank on my 86 FJ so i hooked a hand held vacuum pump to the petcock and found it would not hold vacuum. The petcock worked as long as i kept pumping but would leak down as soon as i stopped. I replaced this petcock about ten years ago so i was not expecting it to be bad again. I bought a rebuild kit from RPM but it made no difference. Is there something else i need to do when testing it other than just the vacuum pump? Any help would be greatly appreciated.
pwhitacre,
I can guess two possibilities, from here:
1. Ten years is long enough to expect a re-work of the vacuum petcock to come due.
2. Your vacuum pump or the hoses are leaking air back in, not the petcock itself. FWIW, you can use a good hose and apply your mouth vacuum to open the petcock (it doesn't take much vacuum to open the petcock). Cap or pinch off the hose firmly, and see if the petcock keeps flowing fuel. If so, then the pump or the its' old hoses are bad, not the petcock.
My US$.02 worth . . .
:yes:
.
Check the tube/hose as it can be the leak source. The connections on either end of the hose/tube as well.
I had the same problem it was still leaking vacuum after replacing the membrane .It turned out to be leaking air on backside where the
wires that adjust how much fuel flows goes in .Read the last in my post here :If you plan ti fix it same way i did be sure to use fuel and heat resistant silicone.
http://www.fjowners.com/index.php?topic=19388.0 (http://www.fjowners.com/index.php?topic=19388.0)
Hi
Some FJ1100/1200 guys in Germany, build in a fuelpump, like the later FJ1200 models, and that seems to work fine...I put in a Hardi Marine Fuelpump, German made, works fine.
Cheers, Tom.
....hold on a sec .... isn't there a tiny little pinhole airbleed made into the petcock? , ....as in 'its not supposed to hold vacuum 100%'
..seems I remember a discussion about this umpteen years ago.
Quote from: TomJK on July 29, 2020, 07:39:52 AMSome FJ1100/1200 guys in Germany, build in a fuelpump, like the later FJ1200 models, and that seems to work fine...I put in a Hardi Marine Fuelpump, German made, works fine.
Cheers, Tom.
Tom,
Hardi makes many fuel pumps, both automotive and marine. Do you know which marine fuel pump you have there?
Before installing the fuel pump, did your bike have a fuel pump, or gravity-feed fueling originally? Did you need to replace any carb parts, to suit the pump?
Thanks,
.
I know my vacuum pump is good as i can disconnect the hose from the petcock and put my finger over it and the pump does not leak down. I did notice on the petcock there is a small round area that looks like it could be some sort of a vent and if i put my finger over it the leakdown is slower but still leaks down.
When I rebuilt my petcock it held vaccuum pretty well, that was with a syringe test. I would not be surprised if it needed to be rebuilt after 10 years. When you just rebuilt it did all the metal look clean and in good condition? Diaphragm not pinched anywhere? I don't expect these to hold perfect vaccuum but on a short timescale I would expect them to hold well.
Here is a pick explaining the backside petcock air leak.
I appreciate the pic of sealing the wires, i had read that post when i started trying to figure this out and tried it on mine but it did not help. I guess i will order a new one from RPM. Thanks to all for the input.
Quote from: pwhitacre on August 01, 2020, 03:39:12 PM
I guess i will order a new one from RPM.
If you can live without that wonky reserve, the '84/85 petcocks are plug and play for less money.
You can then re-purpose that reserve rocker switch for something useful....
Sage like words as always from Mr C. My petcock did it to me on a trip this time last year. Replaced with the earlier, non electronic model. Also cheaper to boot. RPM made life easy. And back on the road again.
Hi
I already had a fuelpump, but i know from German FJ riders, that they just fitted the pump on an older, non fuelpump FJ, if they had to change from 8 to 6 mm diameter fuelline I have to ask...
I will try and find the type I used...
Cheers, Tom.
Quote from: pwhitacre on July 29, 2020, 09:23:30 PM
I know my vacuum pump is good as i can disconnect the hose from the petcock and put my finger over it and the pump does not leak down. I did notice on the petcock there is a small round area that looks like it could be some sort of a vent and if i put my finger over it the leakdown is slower but still leaks down.
Quote from: TomJK on August 05, 2020, 09:57:34 AM
... i know from German FJ riders, that they just fitted the pump on an older, non fuelpump FJ, if they had to change from 8 to 6 mm diameter fuelline I have to ask...
Hello Tom, a couple of things to do if you want to retrofit a fuel pump on to your early '84-87 FJ.
1) the '84-85 vacuum petcock must be set on (P) Prime (open all the time) For '86-87 petcocks that don't have this prime feature, you have to convert to a manual petcock or use a '84/85 petcock.
http://rpmracingca.com/proddetail.asp?prod=M%2FC%3AFJPetcock (http://rpmracingca.com/proddetail.asp?prod=M%2FC%3AFJPetcock)
The closing of the petcock is no longer needed, the fuel pump now controls the fuel flow.
2) The '84-87 gravity feed carbs use larger float needle seats, the '88-95 fuel pump carbs use smaller float needle seats, so you will need to change them: http://www.fjowners.com/index.php?topic=9836.0 (http://www.fjowners.com/index.php?topic=9836.0)
If you use the large needle seats with a fuel pump, the higher fuel pressure will push the float needle off the seat and not allow it to fully close and flooding will occur.
3) Add a safety shut off for the fuel pump. On the '88-95 Fuel pump FJ's the fuel pump power circuit runs thru the ignition box so when the ignition box stops sensing a tach signal (engine stopped) the power to the fuel pump stops after a few seconds.
You need to add this Safety feature to your early FJ: http://www.revolutionelectronics.com/Products/Fuel_Pump.html (http://www.revolutionelectronics.com/Products/Fuel_Pump.html)
Everything else is straight forward, pump, wiring, fuel filter, fuel line, etc...
Cheers. Pat
Hi
I use the Hardi 13312, asked the guy who mounted one in the old type FJ1200, he just used the 12 volt that drives the CDI and so that will go over the killswitch, over a relays, the bike runs fine, pumping stops as floats are up, like the normal fuelpumps in the FJ, no more extra actions needed, no problems, has run a over 1000 miles now.
It seems a lot easier than sticking to the old petcock rubbish.
Cheers, Tom.
Quote from: TomJK on August 06, 2020, 04:17:34 AM
Hi
I use the Hardi 13312, asked the guy who mounted one in the old type FJ1200, he just used the 12 volt that drives the CDI and so that will go over the killswitch, over a relays, the bike runs fine, pumping stops as floats are up, like the normal fuelpumps in the FJ, no more extra actions needed, no problems, has run a over 1000 miles now.
It seems a lot easier than sticking to the old petcock rubbish.
Cheers, Tom.
But lets say someone with a older type fj 1200 wants to convert to a hardi fuel pump. Can they just use the old style petcock or du they need to buy a new type fuelpump petcoock first ? im asking because the old style petcoock is opened with vacuum and what about the vacuumhose then ? Does the newer type fuelpump petcoock fit on a 86-88 fueltank ? Where on the bike do you fit the Hardi pump ?
I think the old style petcoock works perfect exept when it starts to leak after 30+ years.
Quote from: TomJK on August 06, 2020, 04:17:34 AM
......It seems a lot easier than sticking to the old petcock rubbish.
Also to consider....with a fuel pump, you can now use a "real" fuel filter.
Something to think about as our steel fuel tanks get older.
Quote from: Old Rider on August 06, 2020, 09:53:11 AMBut lets say someone with a older type fj 1200 wants to convert to a hardi fuel pump. Can they just use the old style petcock or du they need to buy a new type fuelpump petcoock first ? im asking because the old style petcoock is opened with vacuum and what about the vacuumhose then ? Does the newer type fuelpump petcoock fit on a 86-88 fueltank ? Where on the bike do you fit the Hardi pump ? I think the old style petcoock works perfect exept when it starts to leak after 30+ years.
Old Rider,
The vacuum-actuated petcock has a selector switch, for Off-On-Prime. Off means off, On means vacuum actuated, and Prime means free-flowing. If you added a fuel pump, I believe you could set the vacuum petcock to the Prime setting (just a twist of the screwdriver) and forget it. Cap off the vacuum line for the petcock, certainly, where it goes into the intake system.
Please be aware that in an accident, the added fuel pump will not shut off when the engine stops, where the vacuum petcock
would shut off then. You may want a tip-over switch (or similar safeguards) to prevent the fuel pump from running after an accident. If the fuel system is damaged then, the fuel pump could empty the tank, creating a serious fire hazard, unless you can shut off the power to the fuel pump.
.
Quote from: TomJK on August 06, 2020, 04:17:34 AM
I use the Hardi 13312, asked the guy who mounted one in the old type FJ1200....
I was reviewing the Hardi 13312 specs and I see it's a diaphragm pump
https://www.timelessautoparts.com/product/hardi-fuel-pump-13312/ (https://www.timelessautoparts.com/product/hardi-fuel-pump-13312/)
Question for Tom, when this pump is off, does it hold back the flow of fuel?
Some do, some don't....
You want to use a pump that holds back the fuel flow (from tank head pressure) when not running.
Quote from: red on August 06, 2020, 10:57:06 AM
.....Please be aware that in an accident, the added fuel pump will not shut off when the engine stops, where the vacuum petcock would shut off then. You may want a tip-over switch (or similar safeguards) to prevent the fuel pump from running after an accident. If the fuel system is damaged then, the fuel pump could empty the tank, creating a serious fire hazard, unless you can shut off the power to the fuel pump.
.
I'm with Red on this one....if your engine stops, the fuel pump should stop.....period.
The fuel pump safety controller in my link is only $65, which is chump change considering the consequence.
I was in a sudden low side accident where my bike ended up 50 ft away from me. With my chest injury I could not get over to turn my bike off, so I know first hand that there are times when a fuel pump safety switch is a damn good idea.
Quote from: red on August 06, 2020, 10:57:06 AM
Quote from: Old Rider on August 06, 2020, 09:53:11 AM
The vacuum-actuated petcock has a selector switch, for Off-On-Prime. Off means off, On means vacuum actuated, and Prime means free-flowing. If you added a fuel pump, I believe you could set the vacuum petcock to the Prime setting (just a twist of the screwdriver) and forget it. Cap off the vacuum line for the petcock, certainly, where it goes into the intake system.
Please be aware that in an accident, the added fuel pump will not shut off when the engine stops, where the vacuum petcock would shut off then. You may want a tip-over switch (or similar safeguards) to prevent the fuel pump from running after an accident. If the fuel system is damaged then, the fuel pump could empty the tank, creating a serious fire hazard, unless you can shut off the power to the fuel pump.
.
The 86-88 FJ1200 does not have a selector switch only the FJ1100 or FJ1200 made after 1991 has .So if i wanted to convert to a pump i think i had to replace the petcock with a 1991 petcock (if it fits the tank) or the FJ1100 petcock.
Quote from: Old Rider on August 06, 2020, 12:13:28 PM
The 86-88 FJ1200 does not have a selector switch only the FJ1100 or FJ1200 made after 1991 has .So if i wanted to convert to a pump i think i had to replace the petcock with a 1991 petcock (if it fits the tank) or the FJ1100 petcock.
Nope, Sorry, the '89-95 fuel pump petcocks will not fit the early '84-87 fuel tanks.
Like I said, if you have a 86/87 petcock, you need to replace it with a 84-85 petcock (with Prime function)...or convert over to a aftermarket manual Pingel petcock (see my RPM link)
....or convert over to a '89-95 fuel pump tank and petcock...but that's silly.
Hi
It stops fuel coming through when engine is off or kill-switch is on.
Cheers, Tom.
Quote from: Pat Conlon on August 06, 2020, 11:50:48 AM
The fuel pump safety controller in my link is only $65, which is chump change considering the consequence.
Pat, I can't find the link you refer to.
Noel
Quote from: ribbert on August 07, 2020, 10:40:08 PM
Quote from: Pat Conlon on August 06, 2020, 11:50:48 AM
The fuel pump safety controller in my link is only $65, which is chump change considering the consequence.
Pat, I can't find the link you refer to.
Noel
Noel, it's in the bottom post on page 1. In paragraph 3)
It's been a couple days
Quote from: fj1289 on August 08, 2020, 12:37:53 AM
Noel, it's in the bottom post on page 1. In paragraph 3)
It's been a couple days
Thanks Chris, I found it.
Noel