Fuel Leak

junglejim

junglejim

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Joined
Apr 26, 2012
Messages
2,128
Location
Northern WI
Bike
Tiger 800, NT sold
Sprung a leak.
I have noticed a strong smell of gas in my cold storage machine shed for the last couple days. I checked the snowmobile which I recently refueled. I checked the car which had a leaky fuel filter recently. I checked the truck which I just did some brake line replacement on. No leaks found.

Today I found the leak. There is a LARGE puddle of gas under my NT which hasn't moved in over two months. It is stuck in a corner, blocked in by other items, and covered. So I can't access it much less look for the leak without lots of effort. Before I stored it for the winter I adjusted the valves and changed oil. I didn't disconnect the fuel system in the process, but tilted the tank up and worked around everything. Afterward I went for a test ride and filled the tank with gas and stabilizer. All was well. So then I removed the battery, put it in storage and covered it.

So, today, when we are under wind chill warnings, I'm spending my time thinking about part could be leaking, and how I might deal with it. I doubt if a rodent chewed anything because I stored it with bags of moth balls in strategic places, I have never replaced the plastic quick disconnects as per Honda manual, and I don't want to move a motorcycle that is leaking gas into my heated shop. First clue is that it started abruptly when the weather got very cold. Another clue clue is that my wife has a dead mouse in the heater/deforster of her car.

Any ideas? I plan to attack it in a few days if it warms up a little.
 
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Hard to guess without digging the bike out and looking. Since the tank was raised to do the valves before storage, I would look there 1st. The tank is not overfilled is it?
It seems like someone mentioned a leak when a quick temperature change occured and a gasket surface (fuel pump?) contracted with the cold then stopped leaking when the temp stabilized. I sort of remember something like that but my brain cells sometimes misfire a little bit.
Might also check the evap cannister to make sure all the vac lines were hooked up at the valve check. Maybe excess gas in it coming out?

Brad
 
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Mine did that in very cold temps (near 0F). I had filled the tank prior to letting it sit for a few weeks. Temp at that time was in the mid 30's. Parked it. About a week later the temps dropped, highs in mid 20's, lows near 0. One morning I smelled gas and saw a small puddle under the bike. It did not come from any of the overflow lines and there was evidence of it leaking down the engine case.

I never found out what the cause was, but, suspect a seal someplace. It only did it to me once so I never bothered to try and find the cause.
 
Thanks Charlie b, that is the easiest "fix" there is.

I have moved the NT outside to get the source of gas out of the shed, because a fire is worse than a leak. This AM I siphoned the remaining 3 gallons out of the tank and I'll have to deal with the motorcycle later. I have a project in the shop now that I need to finish. Then I need to get my car in the shop to repair that. THEN I can get the bike in IF nothing else breaks down in the meantime. I've had a bad run of breakdowns lately. Yesterday I had to replace the seal in the front output shaft of my transfer case on my truck. Before that it was replacing rusted out brake lines. And before that it was replacing bearings and seals in the front axel (4X4) - which I had done in a shop - and rusted out transmission cooling lines. All that in the last two months, and the truck only has 71,000 miles on it. Plus I did brake jobs and oil changes on both of our cars, and had to replace a window regulator.

All that maintenance could go away if I'd just spend $75,000 on a new car and truck (which is about 4 times more that I spent on my house and 40 acres in 1972).
 
Anyone living in the cold frozen lands is authorized the right to whine!:)

eldon
 
Update on fuel leak.
I finally got the bike into the shop today, removed the plastic, and lifted the tank to look for the source of my big leak. It appears wet around the gasket between the fuel pump and the tank. I re-torqued all the nuts and none were loose. So I'm assuming the gasket somehow failed/shrunk in the cold weather. That location is about the highest point from which fuel could possibly leak so I'm guessing it isn't one of the quick disconnects that I had suspected.

I ordered a new gasket and next step is to remove the tank and prepare it for a new gasket install. While it is on the bench I may try to rig up some way to put some air pressure in the tank and test it for leaks with soap bubbles. That is sort of a McGyver challenge and something to do while waiting for parts to come in next Thursday.

The cause may be that my motorcycle likes to be in the heated shop rather than the cold machine shed. I've never been one to name my motorcycles, but I'm thinking of some names for this one (not nice names). I only named one other motorcycle, my blue Concours C10. After the motor blew up I called it "Ole Blew".
 
If you follow through with leak testing the tank. Keep the pressure real low, maybe 1/2 psi. Because of the tanks complex shape the forces from the air pressure can distort it easier than you expect. This would be especially true for a tank that is separated by a frame backbone. I don't know what kind of fuel level float the NT uses but it could be possibly damaged also.
I tryed to remove a dent in a tank once and it started to straighten out the tank where the frame rail ran.
Keep the pressure low and it will be fine.

Brad
 
ARKNT said:
If you follow through with leak testing the tank. Keep the pressure real low, maybe 1/2 psi. Because of the tanks complex shape the forces from the air pressure can distort it easier than you expect. This would be especially true for a tank that is separated by a frame backbone. I don't know what kind of fuel level float the NT uses but it could be possibly damaged also.
I tryed to remove a dent in a tank once and it started to straighten out the tank where the frame rail ran.
Keep the pressure low and it will be fine.

Brad
Click to expand...

Agreed. Be careful. You may do more harm than good. :doh1:

Macka
 
Tank pressurisation test completed. No leak detected. I connected a tube to the vapor line and pumped it with a bicycle pump to about 4 psi. (I did that before I read the warning to stay around 1/2 psi. Thanks anyway) I sprayed the bottom of the tank with soapy water and found no leak. However, in the shop the temperature was about 80 degrees F warmer than when it did leak.

The rubber keeper on the plastic retainer was disloged when I first looked at. But the green plastic retainer was correctly seated AND the leak was above that point. So I still haven't positively identified the source of the leak. But I'm hoping a new gasket will fix it. Otherwise I'll have to sell it to someone 1,000 miles south of here.
 
How cold does it get in the building where your NT is parked?
 
I would not be replacing the gasket as I expect the replacement will do the same.

At those temperatures things are bound to shrink so I would like to suggest that the better option may be to simply empty the tank of fuel for winter and refill it when the riding season starts again.

Seagrass
 
Resolution of fuel leak.

I installed a new gasket between the fuel pump and tank. The old one was slightly pitted. No obvious leaking area was observed, but there was an area that didn't look shiny like the rest of the gasket. I'm guessing it was either a bad part or it was damaged by ethanol.

But how can that be? EPA says ethanol won't damage my engine!
 
And, keep in mind that I am 1000mi south of you and mine did the same thing :) Maybe sell it to someone in Hawaii :)

I found it interesting that mine only did it once, despite having other winters where temp got as cold, but, not for as long a time. Seems to have been the below 0F and a full tank that did it.
 
jmoore said:
But Jim that is not you're engine.
Click to expand...

I paid for it - that makes it mine!!!!

Phil said that ethanol wasn't good for HIS engine either, AND it didn't even taste good.
 
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Charlie b, I can't say for sure that my leak was from the cold or from the seal. You theory sounds as good as mine. Mine WAS full of fuel and it WAS cold, so that matches your conditions too. But it was the same way in 3 previous winters with no leaking when it was even colder. I guess the theorys sound good UNLESS you have to prove them. Diagnosing intermittant problems and incomplete failures is always a challenge.
 
junglejim said:
Phil said that ethanol wasn't good for HIS engine either, AND it didn't even taste good.
Click to expand...

Boy, I'll say it didn't taste good. I rode halfway to Alaska before I quit thinking I'd go blind and crash. Yuck!
 
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