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Eliminate fuel pump?

Started by bikemad, March 31, 2018, 07:49:24 PM

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bikemad

Since a lot of the FJ1200's running fuel pumps have pump and carb issues, is it feasable to run an electric shut off valve and gravity feed the carbs?(No fuel pump).I see there are also inline vacuum taps available if that would work.

My FJ1100 runs perfectly with this setup that is std fitment in the earlier models.

Do you need to change the float valves when doing this as I know there is a difference.
FJ1100
FJ1200 3cv

FJmonkey

The FP has a single 6mm inlet tee between carbs 2 and 3. They also get a smaller float valve to deal with the pumps pressure. Some with FP have discovered that they can get home by bypassing the FP and use gravity alone. Might be hard to maintain freeway speeds on a low tank due to low pressure but you can still limp home if you have fuel.

The GF like your 1100 has 2, 10mm inlet tees between 1&2 and 3&4.

If you are making changes to the fuel delivery system please consider safety. Changing from GF to FP can be done with the many aftermarket gizmos to stop the fuel from flowing when it should not. RPM has the parts required to convert the carbs over.
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

ribbert

Quote from: bikemad on March 31, 2018, 07:49:24 PM

Since a lot of the FJ1200's running fuel pumps have pump and carb issues, is it feasable to run an electric shut off valve and gravity feed the carbs?(No fuel pump).I see there are also inline vacuum taps available if that would work.


I'm not sure where you get this idea from, but if anything the GF bikes should be converting to fuel pumps. A low pressure system provides a more reliable fuel supply but the main reason is proper filtration

As for reliability, I would only expect to replace the fuel pump once in the life of the bike. Mine has 200k on the original pump and has had nothing more than the points filed a couple of times. I do however see many fuel pumps replaced while hit & miss trouble shooting when they are in fact not the culprit.

Converting to gravity feed is a backward step and will increase the likelihood of the one thing that does plague FJ's, shit in the carbies!

I've never had a problem with fuel dumping into the engine but I'm often away on my bike and the inconvenience of such an occurrence could be considerable, depending on where I am. To avoid this I use one of these ....



....it's a 12v fuel flow shut-off valve, comes ready with 6mm (1/4") barbed fittings,spade terminals and mounting tabs, default position is closed and has a manual override in the event of failure and it's cheap. I've converted many GF systems to fuel pumps on both cars and bikes but never the other way round.

IMO

Noel

"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

bikemad

Hullo Noel,

The problem I have is my FJ1200 was bought as a non running  project and I've had more fuel carb issues than anything else.
Parked up on the main stand you would have a puddle of fuel under the bike in the morning.
A new fuel pump cured this but I'm not trusting nearly 30 year old fuel systems!


where did you buy the fuel cut off valve?

Cheers Ian.
FJ1100
FJ1200 3cv

Pat Conlon

I'm with Noel (well said) why take a step backwards converting to gravity flow?

I plan on converting my '84 over to a fuel pump, just so I can get away from that wonky vacuum petcock and run a real FUEL FILTER in the fuel line. Alas, like me, the inside of my tank is not getting any younger.

A proper functioning fuel pump will hold back any gas from free flowing when the pump is off.
When the pump is on and you have gas puking out your carbies, it's not the fuel pump's fault.
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

wainot-Phil

Ok  So what is stopping a person  putting a Fuel Pump and inline Fuel Filter on a FJ1100/FJ1200 BIKE that is fitted with a  Vacuum Petcock ,Is this possible ,,if not ,,what is the problem with doing this  ,,I understand that the Needles and seats need to be  changed  going from GF to 12 volt Pump,,,
""Past Bikes""
Suzuki Stinger 125        
Honda 350/4
Kawasaki Z1000
Suzuki GS1000
Kawasaki GPZ900R
Yamaha FJ1100 84
Yamaha FJ1100 85
1991 FJ1200
1990 FJ1200  Pinky
2006 FJR1300
1980 GS850
Z500 /4
XJR1300
"""Present Bikes""": 
  1985 FJ1100
FJ1200  94
GSX1400

ribbert

Quote from: wainot-Phil on April 01, 2018, 01:34:51 AM
Ok  So what is stopping a person  putting a Fuel Pump and inline Fuel Filter on a FJ1100/FJ1200 BIKE that is fitted with a  Vacuum Petcock ,Is this possible ,,if not ,,what is the problem with doing this  ,,I understand that the Needles and seats need to be  changed  going from GF to 12 volt Pump,,,

There is no reason at all Phil.

Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

wainot-Phil

Ok  great   ,Thanks Noel ,,
I was hoping  you would say that  because that's exactly the way I have set  my  87  FJ1200 fuel Feed ,,
I  installed a  "New RPM"   1984/1985   FJ1100  Vacuum Petcock , then the Fuel line goes to an inline Filter  ,then to the Fuel Pump under the seat ,then returns via the exact same path and TEE's off with a Brass T  down into the Centre feed into the Carbs ,,
It all seems to work fine ,,
Cheers Phil
PS  Noel ,,Can you please tell me who supplies the inline 12 volt Fuel switch that you have pictured?
""Past Bikes""
Suzuki Stinger 125        
Honda 350/4
Kawasaki Z1000
Suzuki GS1000
Kawasaki GPZ900R
Yamaha FJ1100 84
Yamaha FJ1100 85
1991 FJ1200
1990 FJ1200  Pinky
2006 FJR1300
1980 GS850
Z500 /4
XJR1300
"""Present Bikes""": 
  1985 FJ1100
FJ1200  94
GSX1400

ribbert

Quote from: wainot-Phil on April 01, 2018, 04:05:57 AM

PS  Noel ,,Can you please tell me who supplies the inline 12 volt Fuel switch that you have pictured?


A few people have asked about that, here is the link http://r.ebay.com/8UVdbF

It cost AU $27 including postage. It"s the best configured one I have seen yet for our purpose. It is Italian made and ships from Poland.

Phil, do you leave your vac fuel tap on "Prime" now that you have a fuel pump?

Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

wainot-Phil

Thanks for the Link,,,,,,No ,,It is on the ON position at the moment ,It only has the 2 Positions ,  On and Prime   
""Past Bikes""
Suzuki Stinger 125        
Honda 350/4
Kawasaki Z1000
Suzuki GS1000
Kawasaki GPZ900R
Yamaha FJ1100 84
Yamaha FJ1100 85
1991 FJ1200
1990 FJ1200  Pinky
2006 FJR1300
1980 GS850
Z500 /4
XJR1300
"""Present Bikes""": 
  1985 FJ1100
FJ1200  94
GSX1400

bikemad

Thanks for the info guys. I'll stick with the fuel pump and not try re-inventing the wheel!
FJ1100
FJ1200 3cv

Pat Conlon

Quote from: wainot-Phil on April 01, 2018, 01:34:51 AM
Ok  So what is stopping a person  putting a Fuel Pump and inline Fuel Filter on a FJ1100/FJ1200 BIKE that is fitted with a  Vacuum Petcock ,Is this possible ,,if not ,,what is the problem with doing this  ,,I understand that the Needles and seats need to be  changed  going from GF to 12 volt Pump,,,

Hey Phil...You are good to go with the vacuum petcock set to the "Prime" position, and the smaller float seats, no worries there.
However you do want to install a safety shut off switch on the circuit supplying power to the fuel pump.

https://www.ebay.com/i/321185373287?chn=ps&dispItem=1
This unit Monitors the tach signal - as long as there is a tach signal present, the pump is allowed to operate. If the engine stops, so does the fuel pump. Works with both inductive (stock) and square-wave (aftermarket) tach signals.
Turns on an electric fuel pump for 3 seconds on initial key-on. This primes the fuel system and tops off the carburetor's fuel bowls.

The '88+ Fuel pump FJ's already have this function built into the ignition box, which supplies power to the pump.
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

wainot-Phil

Hi Pat ,,,GREAT,,,,,,Thank you very much for the info ,I will look into finding/buying  one of these "Fuel Pump Controllers" and fitting it to my 87 FJ  ,, regards Phil 
""Past Bikes""
Suzuki Stinger 125        
Honda 350/4
Kawasaki Z1000
Suzuki GS1000
Kawasaki GPZ900R
Yamaha FJ1100 84
Yamaha FJ1100 85
1991 FJ1200
1990 FJ1200  Pinky
2006 FJR1300
1980 GS850
Z500 /4
XJR1300
"""Present Bikes""": 
  1985 FJ1100
FJ1200  94
GSX1400