Fuel Pump Woes

Hey all,
I recently saved an '84 Interceptor 500 from being destroyed during stunt bike usage. It had no fuel pump when I bought it, and Honda said it is discontinued. I am currently running it with an automotive "universal" style 12volt fuel pump(1.5 psi/25GPH).
Here's my question:
Is it possible to set this bike up for gravity feed?
I had an '86 before and don't remember it having a fuel pump. Also, I doubt that the universal pump is allowing the engine to attain optimum performance.
Any advice would be greatly apreciated!!!

 

This was from another thread.

 

Thanks guys!
I'll check into that. The automotive fuel pump seems to work OK, but I dont really like having this huge noisy contraption hanging off the side of my bike!

 

Also, does anyone know what the PSI and GPH ratings were on the original pumps?
Thanks

 

The pumps only out out about 1-2psi, so what you have now is ok. As mentioned, gravity feed eliminates this source of trouble. If your pump is working fine you might opt to leave it as-is, it just nice to have gravity feed as a backup plan. I'm not too keen on being left on the side of the road (the pump system has done that to me one time to many) so I get them before they can get me!

 

Yeah, I figured that they couldn't have been very high volume pumps. What was Honda's reason for using a pump in the first place if gravity feed would have worked? Also, did they change anything else with the fuel system when they got rid of the pumps?

 

Jamie, doesn't this mean that "Reserve" becomes unusable? Or that you can not let your tank get down to some specific level? (specifically regarding my '85 700).
I would love to eliminate my fuel pump (my buddy got stranded on his Magna because of his), but I would not want to run out of gas either. On my dirtbikes, If I run out, I can usually lay the bike over and get at least a few more miles out of it. I am not so sure that I could lay the Interceptor over far enough to do the same thing.

Thanks!

 

No, not at all. This is a common misconception. It does not change the operation of the tank or how much fuel comes out. The engine runs the same, you will get the same fuel mileage and the same range from the tank. I have never been able to tell the difference between a bike before and after removal of the pump.

The only thing that I do is to install a sintered bronze fuel filter in the line. These are the types of filters that you would see on a 2-stroke dirtbike. The modern Honda's that come from the factory without pumps do not have a filter at all, so this is just an extra level of security that is not 100% necessary.

 

I assume that Honda eliminated thre fuel pump for reliability reasons, but why did they use them in the first place? Was it just to force fuel through a filter?

 

It was a CYA kind of thing. Somebody must have thought it was necessary at the time. You'll notice that pumps disappeared from all Honda models around 86-ish and did not return until fuel injection showed up.

 

Excellent! Thanks again for checking this out for us! When I cleaned my carbs and had the whole assembly apart, I did notice that there are filter screens at each float valve, that entend about 1/4" into the fuel rail. They would be a bear to get at for routine maintenance, though.
By looking at the bike, and the position of tank in relation to the carbs, it looks like the fuel rail entry point is barely below the lowest level of the tank, but I guess that's all we need! I am pulling mine out today.
Why would you suggest a bronze filter over a standard screen type filter? I have never had problems with the plastic screen types, so I am just curious.

 

My fuel pump works and since a universal pump does the same psi. I would say that it works and don't fix it. But if the pump dies and you don't want to replace it a gravity feed should work just fine. The only time you may notice a problem is if you run out of fuel in the system and that will only happen if you are at extreme high speed and it can't feed fast enough. But if its been tested with just a gravity feed and it works its fine with me. But if you aren't sure about using a filter look at this picture. This filter is filthy because of the gunk in my tank. This is a picture of the carbs before I fixed the fuel line.

:grouphug:

 

I am using a filter, just not a Bronze micro-filter type. Yours looks to be a paper element type. Mine is a plastic screen type. No significant difference for our application, I suppose.

 

That filter is from one tank full of gas. It was cheap so I can replace them as long as I need to until the gas tank is clean. I have one of those washable kind that with a golden filter I might pop that on after a while and see what happens. Any filter is better than none IMHO.

 

In this picture...the outlet of the fule filter connects to the hose that still has the clamp on it and heads over to the right. Where does the other hose connect to (the one that looks like it comes up from a fuel or vent rail, takes 2, 90 degree turns, and looks like it is resting on top of the diaphragm cap)?
Mine is just hanging in the breeze....

 

OK,
So I took my fuel pump off and now the bike('84 VF500F) won't stay running. It will idle, but it seems as if the gravity feed isn't supplying enough fuel to support the engine at higher RPM's, or while the choke is on(it runs fine with the 1.5psi universal pump). It dies after about a minute of running above idle, but will fire back up after I allow the float bowls to refill(I am running an ON-OFF-RES petcock without any vaccuum controled-shuttoff, so the fuel can feed with the petcock set to on or reserve and the motor off). I checked the fuel flow, and it is gravity-feeding 500cc's per minute. Is this less than the required amount? This was on the reserve setting with about 1 gallon of gas in the tank. Any input?
I thought that maybe the carbs were set way too rich, does anyone know what the proper mixture screw setting is(# of turns from bottoming out)?

 

The original picture is after I messed up the routeing and put the fuel line on the wrong side. Here is what it looks like now. With a trimmed gas line where the filter goes into the fuel line on the left side.


The other line just hangs there. However, it is suppose to be between the coils and the thing that the carbs bolt to. I thought that I was missing lines because it wasn't long enough when I put it back together. Not it is and I have enough room to connect the two.

 

I would fill the tank full of gas before trying the gravity feed thing. And route a new line from the tank in a short loop like a backwards C so it goes directly into your carbs intake. Check for a fuel leak too. But it sounds like you are out of gas.

 

Unless your bike empties the tank in under 45 minutes of riding (assuming 22L capacity) then 500cc/min is enough isn't it? I would look for a loop in the line that is dropping below the carb level, or a kink in the line.

One thing that I have wondered though, are there lines inside the tank that make the fuel actually go through a loop or bend that extends above the surface of the fuel at some level? Reason I ask, I have one tank that will run out of fuel (making me switch to reserve) at about half tank. The tank is rusty inside, and to me it makes me think there is a line in the tank that is rusted through, and at half tank it lets air in the fuel line, making it lose prime. I also cannot drain that tank completely, I end up with about a gallon left in it that does not come out.