Moat Plug

[pehayes]

I can't believe I'm the only person with this issue.  I've never heard others discuss it.  1998 EV.  The fuel tank has a flush mount fuel cap.  Around the rim of that cap is a shallow moat.  If you overfill or spill fuel, where does it go?  When you ride in the rain or wash your bike, water gets into the moat.  Where does it go?  The tank has a steel drain tube running from the cap's moat area, through the tank, to an external fitting in the tank tunnel.  Attached to that is a simple drain hose to ground.  If water or fuel gets into the cap moat, it SHOULD simply drain to ground.

However, the tank's internal steel drain tube is small diameter and, in order to tolerate expansion and contraction of the tank, it is formed into a multi-coil within the tank.  Next time your fuel is low, remove the cap and look down inside to see the coil shape of the drain tube.

Now, when fuel evaporates, it leaves sticky residue.  Any dust, grime, pollen, etc. sticks to the fuel residue and eventually completely blocks the drain.  Now, if you ride it the rain or wash your bike, the water does not drain away but fills the moat.  As soon as you remove the fuel cap, some of it spills into the tank and then sinks to the very bottom.  It may periodically get sucked into your fuel stream and cause some performance hesitation.  More likely it will just puddle at the bottom of the tank and eventually rust its way out.

I am a firm believer that this drain system must be tested and verified every time the tank is off.  If you find it blocked, it can be cleaned out a la RotoRooter.  If you ignore it, it may become too blocked to get corrected.

Here is the fuel tank opening showing the tiny moat drain at the rear, center of the moat:


Here is the drain opening below the tank.  From here, a simple hose leads to ground:


Unplugging the drain is VERY difficult.  You need the following tools:


Orient the tank nearly upside down so that the drain exit is the high point.
Spray some carb cleaner into the tube exit so that it softens any plugs and lubricates your roto rooter snake.  BE CAREFUL with the carb cleaner as it will eat your paint.  Pack some protective toweling up in the tank fuel opening.
Use the hand vacuum pump to suck on the exit tube in order to confirm if it is blocked or free.
Ditto with the compressed air gun and tapered tip.
For my roto rooter snake, I used a 13" piece of 1/16" bicycle shifter control cable.  Tin the very ends so they don't fray or unfurl.  I clamped 1/2" in the drill chuck jaws and was able to feed the entire remaining 12.5" into the drain until the chuck literally hit the drain tube exit.
The electric drill allows for slow rotation action while your fingers feed the snake up into the drain.  Go VERY slow or you risk having the cable kink and double-knot. 
It is a very slow, tedious process but eventually I got the blockage free.
Afterwards, I force fed some carb cleaner in both directions to wash out yucky sludge.

I'll gladly do this for anyone in the SF Bay area.  Just drive your tank over here.

While mine is a 98EV, I have to believe this same drain function appears on any of the tanks with a flush mount fuel cap.  Easy to test.  Just raise the tank, disconnect the hose, connect your vacuum pump and give a few strokes to see if it holds vacuum or passes air.

Patrick Hayes
Fremont CA

[Bill Havins]

This message brought to you by "Patrick Hayes" - the developer of fine fixes for '98 EV quirks, including its brittle plastic turn signal stalks.

Bravo!

Bill

[Sasquatch Jim]

  As above but use a hypodermic syringe to apply the carb cleaner.
  Then wear splash goggles or squint real tight when applying 100 pis air pressure to the tube.
  If no air comes out the end by the fill hole, you are screwed.

[Kiwi_Roy]

Patrick,
          On reading this I went straight out to check my EV, sure enough it's plugged solid. Every time it rains or the bike gets washed the water has no where to go but inside.
I have some SSS downrigger line, I will try that. Is it possible to remove the stainless insert from the tank, I took out the screws but it wouldn't budge.

Roy

[pehayes]

Is it possible to remove the stainless insert from the tank, I took out the screws but it wouldn't budge.

Roy

In theory, yes.  I once did another 98EV.  The stainless outer ring came out quite easily and promptly dropped six brass spacers down into the tank.  Can't fish brass with a magnet.  Took quite a bit of time to get them back out.  On mine, I stopped trying to get it off when I got to the point of nearly damaging the tank.  I was even using a body shop hooked 'slap hammer' to try and yank it out.   YMMV.  Some do, some don't.  Depending on your model design, put a big rag in the tank neck to prevent dropping any spacer components inside.

Patrick Hayes
Fremont CA

[Carl Allison]

I wonder if a penetrant like Kroil would be a reasonable first step.

[Loser-At-Life]

Pat, thanks for the thread .

Don't want to hijack a thread, but you answered a question I have with my oilhead .

The 'moat drain' on the oilheads go to a canister, mine is at the right rear of the bike .

I removed it a few years ago to repaint it and got about a pint of old fuel and water out of it, I remove it every year now and drain it !!!!

Again thanks !!!!!!!! :+1

[pehayes]

I wonder if a penetrant like Kroil would be a reasonable first step.

Carl:  Are you referring to an internal soak of the drain tube?  Or are you referring to a loosening of the fuel cap periphery ring?

If the former, then yes, any solvent will work.  Letting it sit softens the plug.  The cable snake tears it up.  And the air gun blows it through.  What is in there is chemical residue from evaporated fuel, mixed with any dust or dirt that has gathered in the moat and has been washed down the tube by rain, bathing, or fuel overfill. 

If the latter, I tried every solvent and lubricant on my shelves (skipping those that dissolve paint) and even blew them around and under with my air gun.  No joy.  That sucker will need to be torched off.  I did get the drain open so I abandoned the ring removal project.

Patrick Hayes
Fremont CA

[ken farr]

................... ....Go VERY slow or you risk having the cable kink and double-knot..........
 

Patrick Hayes
Fremont CA

......or as in my case, a double hitch, square reverse knot....... ::)


Just gotta love the little stuff, cause it leads to so much more.... ;D

kjf
 

[Carl Allison]

Carl:  Are you referring to an internal soak of the drain tube?  Or are you referring to a loosening of the fuel cap periphery ring?

If the former, then yes, any solvent will work.  Letting it sit softens the plug.  The cable snake tears it up.  And the air gun blows it through.  What is in there is chemical residue from evaporated fuel, mixed with any dust or dirt that has gathered in the moat and has been washed down the tube by rain, bathing, or fuel overfill.  

If the latter, I tried every solvent and lubricant on my shelves (skipping those that dissolve paint) and even blew them around and under with my air gun.  No joy.  That sucker will need to be torched off.  I did get the drain open so I abandoned the ring removal project.

Patrick Hayes

Fremont CA

The former. I removed the periphery ring on my Sporti tank and had one of the screws break off. Luckily, there was enough sticking out it could be removed with a vise-grip. I better check that drain though.

[Kiwi_Roy]

Ha, found it.

This is where Patrick tells us how to clear the moat drain common to EVs, Jackals and such beasts

I bought it back to the surface because another member has been asking me about it.

Bump

[maquette]

Ha, found it.
This is where Patrick tells us how to clear the moat drain common to EVs, Jackals and such beasts
I bought it back to the surface because another member has been asking me about it

I was that other member and after three, three hour attempts I finally got it open. I never could get a wire to go all the way through from either end, but I get 100# of air through from either end now. Thank the good Lord for folks like Patrick and Roy. The engineer who designed (?) that drain line should be taken behind the wood shed for a long time.

I wouldn't recommend the way I did it, but it worked for me. I used 17 gauge galvanized wire and pushed it in an inch at a time with a set of needle nosed pliers. I also used small amounts of carb cleaner, brake parts cleaner and acetone. I was very careful and nothing got on my paint.

I will make sure to check this drain several times a year in the future. I installed a new main fuel filter and now I need to put it back together with a new manual petcock I bought.

It's time to let the stress go!   

Tom

[Sasquatch Jim]

  This is the price you pay for having a nice flush mounted gas cap.
 Luddite that I am, I prefer the gas cap that sticks up above the fuel tank
 so that water and debris are not funneled in when you unscrew the cap.