87 VFR 700F2 - Bad fuel pump, carb, or...?

So I'm relatively new to VFR but diving in head first into the shallow end of the pool. I've replaced all pads and rotors all around, swing arm, handlebar clips, rubber, and now I'm trouble shooting the engine (which has 73,000 miles)

Bike starts great, idles perfect. I head out on my ride and within about two miles the engine dies. Seems to be carb flooding, perhaps by way of over zealous fuel pump (aftermarket percolator version) or pressure regulator failure. I wait a few minutes, turning off the gas tank to dry start, it starts up for about 15 seconds before dying (unless I allow gas to pass).

When the engine dies, it seems like the engine only runs on a couple cylinders, and I have to give full throttle to keep it alive until it eventually just completely dies.

Oh yeah, the clutch cover, etc. assembly at the right foot steams off like a hot shower.


I'm hoping this is just a simple fix, like everything else I've encountered and I just need to change the fuel pump or press reg but looking for some confirmation or get pointed in the right direction or some ideas. Like I said I'm new to VFR but pretty handy mechanically but not a mechanic.

 

First of all if you have to remove the carbs, do so as a complete set--don't remove the plenum plate. D/L the service manual or search here for how (and how not) to remove them. Your carbs may be gummed up inside and will need to be cleaned.

Do you have to use the choke to start it and/or keep it running? Has the bike set up for a long time such that the fuel may have varnished and gummed up the carbs (or tank, or fuel pump) internally? There is no fuel pressure regulator on these bikes, that function is done within the stock fuel pump.

Is the hot steamy shower from water dripping on the clutch cover, or some other wet dream liquid?

There are some carb bowl drain screws on each carb with little nipple ports. You could try putting a piece of small clear fuel line tubing on the port and open the screw to see how high the fuel level is in each bowl. If its flooding then the levels will be high, but if it starving for fuel, which is my guess that is your problem, then the level will be low. Or there may be some debris in the bowls--drain them and catch the fluid, inspect for debris, etc.

 

START by inspecting all 4 plugs. If one or more are black--rather than the medium tan color that's ideal--you might have a leaky float needle/s.

On the other hand, if plugs appear whiteish, you might have clogged jets as KB suggested or a failing fuel pump or obstructed fuel filter.

 

Thanks guys. I'm gonna start with the fuel pump and filter and then move to the carbs if need be. What's wierd is that it idles fine hot or cold, goes fine hot or cold for about 3-5 minutes then bogs out. Choke cable is just about broken so I keep just a little choke on all the time (I know, I know) just enough to get it started.

Speaking of the choke cable, anyone have any ideas to easily remove the airbox? The screws I see on the top seem pretty small and don't want to strip them..

Thanks again!

 

As described it is a bad fuel pump.

 

just unscrew them.. it is a plastic air box.... you gonna have to take it off to get the carbs out.. and having the choke "on" will kill the bike after it warms up... you are basically flooding it with fuel...

 

Where are you located? If your close enough I will unfuck this for beer while you wait.