So youve filled Diesel in your R1250GS

listermint

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Ah yes via muscle memory (volvo) or just pure blissful unawareness I put Diesel into the 1250, how could one do such a thing you ask ? Life! Shit happens.

Anyway thought I'd put together a quick thread on learnings to correct such a scenario. It was about 3/4 tank so I took off unknowing up the motorway with diesel in the tank. She lost acceleration first when twisting and felt like it was going to cut out. Did this for a few kms. So pulled off at next junction and headed home on backroads. Then threw up workshop warnings in orange then red. So pulled in (at this point I didn't put 2 and 2 together assumed some bad petrol).

So had a look around at connections to sparks and lines etc couldn't see anything so called road side assist for Tow home. Whilst waiting 90 mins for them I flashed back in my brain to picking up the black handled pump and the sense of dread swept over. Fk it you fool.

So got home in back of van with firm direction to sort it out. Haven't had the GS tank off before so wasn't sure what to expect. (Tank removal is not required, cover this later)

First port of call drain the tank out. I recommend an oil pump, I've a small one from lidl that connects to 12v battery. Took a 5 mins to drain the full tank into a 25 litre drum I have around.

Then stripped the plastics (plenty of youtube videos on this but is fairly straightforward)

Removed tank , it has 1 fuel supply line and 2 electrical connections. I took it off to see what was beneath. But the fuel line just goes straight to a T and out either side to the injectors. The pump and filter built into tank. I turned tank on its side and used pump to take any last remnants out of it. See tankless picks.

I then used a shop vacuum to suck anything out of the fuel lines to the injectors (probably pointless there's a simpler way)

Removed injectors to see if they had any clogging. Cleaned them off and then removed plugs to clean them off. Put the tank back on and connected everything put petrol into it and tried starting. Not much joy and the battery was starting to drain.

So now to the proper way ! In 5 mostly easy steps.

You can leave the tank on for all of this and the plastics.

1 - Empty tank of diesel.

2 - Disconnect the fuel lines from the injectors each side. There is a copper square clip that holds the lines 90 degree connector to the top of the Injector . You'll have to Removed the T25 from the connector fixing bracket and give the 90degree elbow a few solid tugs to get it off the injector. Pic below.

3 - throw in about 4 litres of petrol into tank and put each fuel line into an old jar, turn the power button on don't start the bike. This will cycle the fuel pump from the tank and petrol will pull through the pipes to clear out any diesel into your jar, power button on and off a few times to cycle petrol through the filter the pump and the pipes. I did this about 10 times

4 - Now the injectors, if you drove bike like me they'll be stuff full of diesel. If you haven't you'll get away with not doing this bit. Remove injectors from cylinder head just pull out. They have 2 electrical connectors on them which open the injectors to allow fuel in. You can open and close the valve with a 12 volt battery and some crocodile leads. I put some carb cleaner in the end and opened the valve with the 12v you should hear tiny click. Just blew through them with my mouth and the cleaner and diesel crap should spray out in a couple of Vshaped patterns. I did this a few times to each injector to make sure cleaned out. Then ran some air through it to dry.

5 - finally the plugs, remove the plugs and using a lighter dried them out. Noticed the tolerances were way off on both so adjusted them (plenty other information out there on this)

Now put it all back together and powered the button a few more times to prime the lines up with fuel. I started the bike 3 times but she was struggling, it did fire and die. So had to add a portable battery charger to boost. She fired up straight away and nice poof of diesel smoke out the back for a few minutes until it all burned away. Left it to run for 5 minutes then stopped and started to make sure she was working. Needs a good solid hot ride out to burn away any remnants. But back to normal. Warnings cleared after a few starts.



So there you go. Don't be a wally, but if you are see above. Best of luck!

Advise swapping plugs and an oil change for precaution.

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Noted and bookmarked - thanks. You say you don’t need to remove the tank to remove the fuel lines, is that correct? I was just trying to figure out where the second photo is on your first photo?
 
Noted and bookmarked - thanks. You say you don’t need to remove the tank to remove the fuel lines, is that correct? I was just trying to figure out where the second photo is on your first photo?
I did that to see what was below. Turns out fk all. The fuel line comes direct from the internal fuel pump in tank to a T and out to both sides into injector. Tank removal is not required at all. But sure I cleaned all the back of the plastics and everything underneath whilst I had it all off.

But entire process can be done by leaving the bike as is, and just removing lines from the injectors on top of cylinders.
 
With 2 diesel cars in the household that I refuel constantly (it seems) it was a natural reflex to select the black pump, but I’d only put about 10 litres in before I realised and almost screamed.
Fortunately I hadn’t started it so I pushed the bike off the pump, paid for the damned diesel and called a mate who arrived with a 5 gallon can and a length of tubing. After he’d siphoned the diesel out I refilled with unleaded plus and started the bike… lots of smoke for a short while and initially ran a bit rough, but finally cleared.
The bike was a bit hesitant starting for the next few days but soon back to normal. :) A close shave and something I now double check each time!
 
I've done this (filled a GS with diesel) it rode for about a mile and I got it recovered.....you know the rest.
It wouldn't have occurred to me until this point that a diesel fuel dispenser fits the filler neck on a bike, unlike cars which have a narrower filler neck to accommodate the unleaded dispenser only, so if your mind is not on the job or you get distracted by, for example, a person on the neighbouring pump talking to you, it can happen, that's my excuse and I'm sticking to it.
 
Good info there. Thanks.
I've done it myself, but put petrol on my Diesel Ford Ranger. That was easier to sort out. Thankfully.
 
Actually curious how the nozzle actually fit?! More common petrol in diesel cause smaller diameter


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Actually curious how the nozzle actually fit?! More common petrol in diesel cause smaller diameter


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It may be a smaller opening on a bike but a diesel nozzle would still fit in. I suppose this is because you don't see diesel bikes too often.
 
Many Bikes don't have the narrow filler neck as diesel bikes are so rare they're irrelevant, the filler on my GSA is easily wide enough for a diesel pump. I just have to avoid the dreaded Brain Fart...
 
Many Bikes don't have the narrow filler neck as diesel bikes are so rare they're irrelevant, the filler on my GSA is easily wide enough for a diesel pump. I just have to avoid the dreaded Brain Fart...

Ah, I knew it was a stupid question right after I asked, but not before I sent! Lol
On a lighter note, diesel shouldn’t do much long term damage to petrol engine. Two oil changes and new spark plugs……….followed by hot breakfast


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Petrol engines are way less sensitive to diesel than a diesel engine is to petrol, the reason is that diesel is oily so performs double duty as a lubricant in the high pressure pumps, petrol is a great oil remover so the pumps grind themselves to death very quickly.

Diesel will lower the octane of petrol though and is not the best for the catalyst, but 2 oil changes and new plugs is overkill, I would drain the tank, refill with high octane and let it run until the fans cut in which should be long enough to flush the lines and injectors, then ride gently for a couple of miles and carry on as normal after that.
 
Done twice. VFR anniversary on the way to Cadwel-7 hours for the AA to responsibly get ride of the diesel and come back with the tank.
Once on the KTM 1290 , a mile from my house and the odometer read 130miles total. Didn't start this one unlike the VFR which smoked all the way home cuz the rest left me in a fit of laughter :LOL:
 
I'm still trying to work out how diesel would have got into the oil... :duno :nenau Do tell

Not much, but the combustion chamber is still inside the engine(obviously) and might get past the piston rings or valve seals since thinner than oil. I’d still change the oil. Never wronged my fuel so hypothetical


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Having a diesel car this has always been a worry, i always double check at the pump when on the bike.
but i can understand how its easy done.
 
Stopped on the way home one night and Pput about 10 litres of desiel in the GS before i realised and stopped filling. Dark and cold I thought , feck it , and decided to fill her to the brim with the good stuff. She rode a little rough and a bit smokey but got home , petrol station across the road so put another gallon or so of the good stuff in to dilute the diesel . . Did the same thing the next day , rode about 60-70 miles , brimmed , rode home…… fill rode repeat. Bike was fine .
 
Not much, but the combustion chamber is still inside the engine(obviously) and might get past the piston rings or valve seals since thinner than oil. I’d still change the oil. Never wronged my fuel so hypothetical


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It’s waaay too much. Changing the because there might be a chance it got diesel in it is akin to replacing the front tyre because the back is punctured. I’ve done it twice once in bike and once in car. The car was diesel. Sorted it myself with no fuss. JJH
 
It’s waaay too much. Changing the because there might be a chance it got diesel in it is akin to replacing the front tyre because the back is punctured. I’ve done it twice once in bike and once in car. The car was diesel. Sorted it myself with no fuss. JJH

………..like I said, hypothetical


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Petrol into a diesel is far worse than diesel into a petrol. Apparently the petrol knackers the seals in diesel fuel system. Big bills to repair.

I’ve done the same as you - I’ve had diesel cars for years and years and started to fill a CRF 250 with diesel . Only got about a quarter litre in before I realised but as it’s a small tank I was a bit worried how it would go. Brimmed it with petrol and didn’t have any issues, thankfully.
 
You will get away with up to 30% either way. The more modern the engine the less forgiving. I put 35 litres of petrol into a diesel alamhra and it was bad. Very smooth though. Pig to start. The minute I had room in the tank I just kept topping up with diesel. I put 27 liters of diesel into a f800gsa (yes I know it’s a 24 litre tank). Had to drain and refill. JJH
 


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