Topic: Fuel filter question

[.jordan]

When I rebuilt the carbs and put a new tank in, i threw an inline fuel filter in to make sure no crud got in the carbs. well i pulled the carbs again for a little tuning as the bike was apparently running a little lean. When i put the carbs back in i left out the fuel filter since nothing had collected in it. The bike was only running on 3 and 4 cylinders and wouldn't hold an idle. just for fun i put the filter back in to see if it made a difference and it was back to its normal...lean self. So I'm wondering if the bike was just running overly rich without it? and thats why 1 and 2 werent firing, or what? anyone have similar experiences?

[manjisann]

I ran a fuel filter on my 500 and never had an issue. If the filter is restricting the flow, change it. You either have the wrong type of filter or it did it's job and is now plugged up.

Just my .02

Brandon

[mystic_1]

Any differences in your fuel line routing when you're running with or without the filter?

If anything, adding a filter could make the bike run worse (if it's causing restrictions) or no different at all.  If installing hte filter actually makes the bike run better than I'd suspect another problem in there somewhere.


mystic_1

[TwoTired]

Fuel delivery is a gravity feed system.  It should be plumbed so there is a constant, drop between source and destination as the only pressure that pushes the fuel through the line is generated by gravity on the column of fuel directly above the fuel tap on the tank and the fuel in the drop between tap and carb inlet valve.  If any of that fuel has to rise back up, fighting gravity, this subtracts from the fuel pressure on the carb inlet valves.

Air can and will get into these fuel lines an those "bubbles" will try to reach the surface of the liquid (normally inside the fuel tank).  This creates back pressure.  More air means more back pressure.  And, particularly when the fuel level in the tank is low, less fuel pressure and flow that makes it to the carb inlets.

Honda put a fuel filter in or before the fuel tap for a reason that few seem to understand.

[mystic_1]

I suppose I could see it if the filter is causing restriction, and you compensated by for example raising the floats to let in more gas, then the bike would run rich when the filter was removed.

TwoTired is right that there's a filter in the petcock so that should be all you need, unless your petcock filter is missing or damaged.

What bike is this?

I'd recommend removing the inline filter and then checking your float adjustment, idle mixture, and carb sync.  Let us know what you find out.

mystic_1