Fuel Pump and Filter

[fj1289]

Not sure that I've ever seen a totally stock FJ!  And can't get to my manuals right now, so here's a question for the fuel pump equipped bikes - do they come from the factory with the filter before or after the pump?  Wonder if it is better set up with the pump pushing through the filter vice pulling through the filter?

[aviationfred]

According to the diagram, the fuel filter is on the inlet side of the fuel pump.

http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1989/FJ1200W/FUEL+TANK+%28NON-CALIFORNIA+MODEL%29/parts.html


IMO, I would want the filter to catch all contaminants before it could clog the fuel pump.

Fred

[TexasDave]

Sorry Fred this argument has been going on for years among autmotive hot rodders.  Pump mfgs recommend the filter after the pump so the gas supply to the pump is unimpeded and the pump has a good supply so it doesn't burn up. Some hot rodders claim with a starved pump it cavitates and vaporizes the gas in the line.  Dave

[Canuck FJ]

Stock location is filter before pump, presumably so that any debris is caught before it trashes the pump.

[Capn Ron]

Not sure that I've ever seen a totally stock FJ!  And can't get to my manuals right now, so here's a question for the fuel pump equipped bikes - do they come from the factory with the filter before or after the pump?  Wonder if it is better set up with the pump pushing through the filter vice pulling through the filter?

The factory setup (as Fred pointed out) is Tank-Filter-Pump-Carbs.  Better?  That's a pretty open ended question.  Customers used to come into my bicycle shop and fully half would lead with the question, "What's the best bike to buy?"  I'd always reply, "Best for what?"

What is it you're trying to solve or improve upon?
Better filtering?
Cavitation issues?
Pump temperature?
Physical space for a filter?
Maintenance convenience?
Pump longevity?
Fuel pressure?
Fuel flow?
Stock appearance?
Smaller micron filter use?

Improving on one of the above likely degrades one or two of the others above.  I like questioning things and learning in the process, but the fuel filter/pump setup isn't something I've ever considered to have a fault...so I've not questioned it.

[TexasDave]

Stock location is filter before pump, presumably so that any debris is caught before it trashes the pump.

In my Ford P/U there is a sock screen on the inlet side of the fuel pump. In the fuel line after the pump going to the carburetor there is a fuel filter. Then in the carburetor inlet fitting there is another fuel filter. I think automotive mfgs are more worried about the carburetor or injectors getting plugged up than the pump. This is starting to sound like a hot rodders forum.  Dave

[rlucas]

This is starting to sound like a hot rodders forum.

Wait...you mean it's not?

Oh. Sorry. I thought you said hot modders forum.

[ribbert]

IMO, I would want the filter to catch all contaminants before it could clog the fuel pump.

Fred

I think the location of the filter on the FJ is determined by practicality rather than showing a preference for before or after.

Fuel pumps are not sensitive to contaminants like carbs are, they do not have tiny orifices and only require the commonly fitted screen filter on the pick up or tank outlet.

Fuel filters offer so little resistance to flow I can't see a valid case for one over the other. Hot rodders may wish to expound theories and throw jargon at each other but I don't see the case for push vs pull is significant enough to even bother discussing it.

Of all the reasons that might go into where best to position a fuel filter, which side of the pump it's on is the least important. Most cars have for decades now, and probably many bikes, have in tank pumps and the filter has no choice but to be up stream of the pump.


Noel

[fj1289]

Agreed in which is best -- it depends !

Another question/twist -- what TYPE of pump is the stock pump?  A diaphragm pump?