Freshen-up your bike’s fuel
The quick, easy and safe way to rid your motorcycle’s tank of stale, old petrol
1 Bike been laid up?
If your bike’s been stored it’s easy to assume that you’ll need to strip injectors and fuel pumps to assess any damage caused from stagnant fuel but it’s always wise to try starting the bike up with a fresh tank of fuel, as it could save work. First, shine a torch into the tank to assess how much old fuel is in there, then find a suitable container for the fuel to be drained into. Remove the bike’s battery and place it on charge.
2 Open wide…
Petrol vapour is very flammable, even ancient old stuff that’s lost most of its zing is still pretty volatile. You should maximise any ventilation by opening all the doors and windows in your work area. Make sure that the bike’s ignition is switched off and that there are no potential ignition sources in the area. Ideally you should conduct the whole procedure outside.
3 Don’t get a mouthful
Gone are the days when people used to cut a length of garden hose and physically suck fuel from their tanks! This practice meant there was always a high probability of getting a toxic mouthful of petrol. Most motoring shops sell various types of pumpaction syphons – this decent-quality Draper one costs just £13 but you can pick them up for as little as £3.
4 Get it all set up correctly
Have a look under the tank to see where its lowest point is. Sometimes it’s not obvious as often the depths are hidden under fairing panels. When you’ve located the lowest part of the tank insert the syphon pipe into it. Often the syphon will have a direction arrow printed on it and if there is ensure it is pointing in the direction of the fuel container.
6 Time for some fresh gas
When all the fuel has been drained, remove the syphon – taking care not to drip fuel on your bike – then peer inside the tank with your torch to check that all the old fuel has been drained out. When you’re satisfied it’s empty, fill a jug with a measured amount of fresh petrol and pour it into the tank via a filtered funnel.
8 Use some persuasion
Press the starter. You should expect it to take a little bit of time before anything happens, so try for three or four 15-second bursts. If the bike is still refusing to start, squirting some carb cleaner or starting agent into the air intake can help. Once the bike fires let it warm up slowly, check around the engine for any oil, fuel or coolant leaks. Expect a slight burning smell from the years of dust burning off the downpipes.
5 Now get pumping
Pump the syphon until you see the petrol start to rise through the pipe, and as soon as you see it pass lower than the tank you can let gravity take over. You need to make sure the end of the pipe in the tank remains at the lowest point. Check that as the jerry can fills up there is still sufficient volume for the remainder of the petrol in the tank.
7 Don’t ignore the other fluids
As the bike has been standing for a few years it’s best to check the oil level prior to cranking the engine. If the bike is watercooled you should check and top up the coolant level if necessary. Refit the fully charged battery and switch on the ignition to check the lights and prime the fuel pump.
9 Take it for a (gentle) spin
If you’ve still got a valid MOT, give the bike a road test. Ride it gently with modest revs at first, then increase both the rpm and throttle opening. You need to make sure there are no flat spots and that the bike accelerates through the gears smoothly, right through the rpm range with no stuttering in the fuelling. This can also be carried out on a dyno if you have access to one locally.