Draining a Fuel Tank - How?

[Cillit-BANG]

I'm about to replace the fuel filter on my Ducati 750ss.

The wonderfull Ducati manual explains everything from pumping up your tyres, to full on engine strip, but no where does it explain how to drain the chuffing fuel tank. Instruction starts with 1) drain fuel tank FFS.

So, is it a case of externally syphoning off the fluid, or is it drained from a fuel-line? If it is the latter, if I disconnect the relevent pipe, I'm assuming there is a diaphram somewhere (no fuel tap) to stop the fuel pissing out for safety reasons. So in which case, how do I by-pass this to get the fuel to actually piss out like I want it too?

I'm sure it's remarkably simple. I'm quite mechanically minded, in fact I've done most of it's 12k service myself, but this bit is driving me potty.

Cheers in advance.

[stinkwheel]

Does the tap have a 'PRI' position? Use that.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[cagiva gezzer]

Suck on the vacuum line with your mouth as no fuel will come out of it. Use the battery overflow tube to extend put on the fuel tap so you can drain it off.
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"because one stroke isnt enough and four strokes waste two"

[sickpup]

If its fuel injected.

Take the fuel line off the carbs and route into a suitable storage container. Switch the bike on and start the engine and the pump will empty the tank

Carbed.

Raise the tank and the tap is on the under side, its the bit with the dial on it and a pipe coming out.

[owdamer]

You need one of these..............

https://uk.geocities.com/[email protected]/files/pumps.jpg

[Cillit-BANG]

Cagiva Geezer, no fuel tap on bike

Stinkwheel, no fuel tap on bike.

Sick-pup, Yup it's fuel injected, how can I take off the tube that goes to the carbs?? There are non. If I remove the fuel line, how will the bike tick over to drain the tank? This I might add has been the best suggestion so far

Judging by the replies, I take it there is no simple way of draining a tank?

[Kickstart]

Hi

You should be able to trigger the fuel pump to run with the engine not running. Might use something like the oil pressure sensor to know the engine is running and so trigger the fuel pump. Or you could just run a line from the battery to the electrical connections to the pump (but be careful doing this, causing sparks while playing with fuel is not a good idea.

Is the pump in the tank or not? Also I presume that there are 2 pipes to / from the tank. One will be a high pressure line from the pump in the tank, one a return pipe from the fuel pressure regulator. Might be that you can just disconnect the return line and drain the tank from there. If you clamp the fuel tank breather hose then the fuel will only run out of the tank very slowly until you get a pipe connected from the tank to a petrol can.

Just a few ideas.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[owdamer]

SEE ABOVE.
syphon pumps are about a quid each on ebay. they work great & you dont end up with a mouthful of petrol.

[Kickstart]

Hi

You can buy automatic siphons where you just put one end in the tank and shake it to start it off.

Remember that if you drain the tank you will still leave the system pressurised so when you undo the filter you will get high pressure fuel peeing out.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Cillit-BANG]

Keith, yup the pump is in the tank.

Under the tank there are 4 connections. 1 pipe marked delivery, 1 pipe marked backflow, 1 marked Drainage, 1 marked bleed. The last 2 are joined via a y-pipe into 1.

So I'm assuming the pipe marked drainage, is indeed for drainage of the tank, but how do I make it drain?!

When the tank is in the upright position, the pipes exit at approximately halfway up. So presumably to drain, the tank will need to lay flat.

[Kickstart]

Hi

My guess would be that the drain pipe goes onto a small spigot with a knurled knob where it goes onto the tank. If so it is probably the same as used on the old Aprilia AF1. This is a tap. Undo the knurled knob and it allows fuel to flow.

Hopefully that is the situation.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[loply]

Drain the tank with a siphon, then run the engine for a minute to empty the fuel rail/injectors/etc?
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[Kickstart]

Hi

Possible, but the pumps need the flow of fuel to stay cool (think that is one reason they are often submerged in the fuel tank).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Cillit-BANG]

No knurled sections, just pipes that join spigots directly from under the tank.

But,

Right. The tank had only 2 or 3 litres left in it anyway, so I remove the filler cap to get access to the fuel pump/filter. I figure its not worth draining anyway. However,

1) Despite the manual clearing showing otherwise, the filter is connected with clips that require new 1's once removed, I have non at home.

2) The tank has developed a load a white crap near the top of tank, presumably it collects where there is usually air space, as the tank is rarely full.

Since it's going in to the workshop to have its belts changed anyway, I'm just going to let them do it They can drain the tank, clean it, and replace the filter whilst they're at it. Shame really because I was in the swing of things.

Good news is that the rest of my first ever service went fine. Bled the clutch and both brakes with no issues, so I'm well chuffed. Although it did require a trip to the dealers for a thermistor which sheared on reassembly, which of course cost £16 for something the size of my thung nail. grrr those gorgous italian bikes

Good weekend tinkering all in all. I feel I have 'bonded'

[feef]

[bidman]

[loply]

bidman, its the fuel that has left the tank, and is now in the fuel line, injectors etc that I believe is the problem?
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Yamaha SZR660 Caution to the wind, the throttle pinned!