Fuel tank leak

[Big Phil]

Hi Guy's, need help yet again! Fortunately it's my old 1999 GSXR750 SRAD (injection) that's the problem though. I have finally got her started after I think 7 years of sitting idle in my garage. I cleaned the tank out and fitted a new fuel pump as it was completely knackered and electrically shorting out. I took the spark plugs out and poured a little engine oil into each cylinder and let it soak for a week. I then turned her over with the plugs out to make sure she wasn't seized and loosen her up a little. Anyway, put the tank back with a little fuel (2/3 pints) and she fired up almost first time Awesome! Sadly though after a couple of minutes running the engine, petrol begins to leak from the bottom of the tank. It's definitely not from the pump gasket or any of the fuel pipes. Without the engine running the leak stops and I can't find where it is coming from.

Any ideas on how to find the leak? Perhaps I can pressurise the tank somehow? If I can find the source of the leak then I can hopefully seal it from the outside. Another option would be to use a tank sealant but how do I ensure the fuel outlets and breathers don't get clogged with the sealant? I am not sure there is enough access to cap off the outlets internally.

My final thought was to buy a replacement used tank but I can only find ones suitable for carburettor versions. It's only a tatty old track bike so I don't want to spend much more cash on her.

As always thanks in advance for any help which is very much appreciated.

[KiwiCol]

If you don't have a compressor in your shed, you can use an old vacuum cleaner on blow to create a bit of pressure, just seal up the gap with something.  I used closed cell foam, cut for a tight fit in the filler hole.  I had a compressor though, but an old vac on blow would work too.

PS, it was on the boat tank, not the bike, much bigger tank at 270L.

[steve porter]

Run the pump without starting the bike and see if it leaks, if not leaking when not running it sounds more like pump, hoses or fuel rail than tank

[Big Phil]

Hi Steve,
               The pump initialises when first turned on at the ignition but how do you keep the pump running without starting the bike? Can I just apply +12V at the connector or does I need any other inputs?

Regards
Phil

[Big Phil]

Thank Col I don't have a compressor but can hook up a garden blower👍

[steve porter]

Not sure, but maybe turn the ignition off and on a few times and check for leaks

[Big Phil]

🤣😂🤣 Sometimes the most obvious things just pass me by🤣😂🤣

[BlueDragon]

Old trick to find leaks.

Take the tank off the bike.  coat it with some talcum or baby powder.

Put the tank back on.

With the bike running, wait for it to leak then turn the bike off.  Take the tank off and where there is wet powder, trace it and you will find the source of your leak.

[grog]

Very clever Bluey. 👍 Dont know if anyone knows, to temporary fix fuel leak not under pressure, just use hand soap. Might get you home one day.

[Big Phil]

Thanks Blue that's a top tip mate👏👏👏👍

[BlueDragon]

Thanks Blue that's a top tip mate👏👏👏👍

If you are just going to use some sort of fuel tank leak repair putty.  I can recommend the Permatex one.

When I first bought my 1400, I ended up finding some pin hole leaks in the tank.  Repaired the first 2 leaks I found with some putty and it worked fine and is stuck solid to the tank, even now, its still stuck on.

Only reason I ended up using a tank liner is because I then found the previous owner had already put a tank liner in the tank but did a crap job of it and it was flaking off in huge chunks.  I documented it in my blog on this site.  So ended up cutting the base out of the tank to remove the old liner and then had it soldered back in again by a car radiator place.  Then put a tank liner through it.

[Big Phil]

Hi Blue,
            That's great to know. My plan, one I have found the leak, is to use a putty on the outside of the tank and was wondering which type to use. I will look for the Permatex one. I did read your thread a couple of days ago on the tank liner you had to replace. That's another reason why I don't want to use one unless I have to as it can be a nightmare if it doesn't bond properly.

Thanks again mate very much appreciated
Phil

[DP1400]

Phil,

Replace all your fuel lines, they perish and/or harden. One will be perished and you`ll not see it. I once had a similar problem with my GSX`R1100. New fuel lines sorted it. Good luck and keep us posted .

[BlueDragon]

Big Phil.

I just followed the directions to the letter on the KBS liner kit and it worked fine.  Not had any problems since putting in the liner.

Previous owner just did a crap job of it and didn't drain out the excess liner fluid.  hence it just congealed into the lower areas of the tank and eventually just started coming off in big chunks as you saw in my blog photos.  Big Mess.

Just takes time and some patience to get the liner to coat the whole tank.

To get the small amount of excess out and also to coat the inner breather lines inside the tank, I used an old artists paint brush that I had (which I was happy to throw away afterwards).  I just used the brush to coat the inner metal breather lines in the tank.  Then used the brush to "scoop" up little by little the excess liner with the tank sitting upside down.  Fuel filler on the ground and I was accessing the tank via the fuel pump hole and fuel sender holes.  Slow process, but I got out most of the excess liner that way.

[Irish in Oz]

Just find the leaks and get them soldered up by someone that knows what they are doing, liner is last resort, but if it's a track bike that will probably be the quick fix.