Help wanted BMW 1250GS is poorly

[timgib]

Hi
I was riding home from the 2025 ABR Festival & things were going well until…….
After filling up with Super Unleaded at the Shell garage around 40 miles from home. I set off & found that every time I opened up the throttle there was hesitancy from the bike before it decided to go, there was also sometimes backfires. I also had my BMW Nav VI acting up & changing screens three or four pages this also happened at least four times on the last forty miles. I was riding with my brother in Law who informed me that the bike was kicking out thick black smoke also. I nursed the bike home & on restarting the bike it only just started & didn’t seem to run healthy it also kicked out the dark smoke when the throttle was opened.
I am wanting any help if anyone can point me in the right direction to solve the problem on my 2019 1250 , thanks in advance all the best Tim

 

[Pukmeister]

Sounds like shit fuel or a dash of diesel.

Best check your receipt !

 

[timgib]

Sounds like shit fuel or a dash of diesel.

Best check your receipt !

Must say that was a thought but I defiantly put in the super unleaded in at the Shell garage that I use regularly.

 

[kevmax]

Check your coils and coil cables.

 

[Pukmeister]

Black smoke is a symptom of excess fuel and/or insufficient air eg terrible combustion. Note it happened as soon as you refuelled.

Have you ingested a plastic wrapper into the intake snorkel/airbox?

Could also be a poor spark or incorrect fuelling by the ecu. Perhaps disconnect the battery and give it 30 minutes to go to sleep then reconnect it and see if it sorts its shit out all by itself ??

I’d be tempted to drain the tank and refill with fresh fuel, sounds like fuel is the most likely culprit to me.

 

[stever1]

Hi
I was riding home from the 2025 ABR Festival & things were going well until…….
After filling up with Super Unleaded at the Shell garage around 40 miles from home. I set off & found that every time I opened up the throttle there was hesitancy from the bike before it decided to go, there was also sometimes backfires. I also had my BMW Nav VI acting up & changing screens three or four pages this also happened at least four times on the last forty miles. I was riding with my brother in Law who informed me that the bike was kicking out thick black smoke also. I nursed the bike home & on restarting the bike it only just started & didn’t seem to run healthy it also kicked out the dark smoke when the throttle was opened.
I am wanting any help if anyone can point me in the right direction to solve the problem on my 2019 1250 , thanks in advance all the best Tim

It sounds like you’ve been the victim of a crossover. That’s when the tanker driver puts the wrong fuel in the storage tank. IE derv in the super unleaded. Or you’ve missed fuelled.
check your receipt to make sure you’ve filled with petrol.
Empty the tank and as much of the fuel line's as you can. Keeping the old fuel.
Refill with petrol and try again. It may be you that’s got it wrong or the tanker
If you’ve done 40 miles, also check the oil level, if there’s derv in the fuel it can get past the rings into the sump. So it’ll be over full and smell funny.
Unfortunately they can’t run for long on the wrong fuel before damage happens. How much fuel did you have in the tank before refilling ?

 

[BillWright]

I can’t help but be simple, open the fuel cap and have a sniff.

There is no way a petrol engine would run 40 miles on diesel unless it was very diluted. Bent valves would be the minimum you could expect as the diesel will not compress.

 

[Pukmeister]

You won’t inject enough in each stroke to bend valves, you’ll just wash down the bores and flood the exhaust system with diesel causing it to smoke like fuck.

Even when our big marine diesels had hosing injectors they wouldn’t bend valves or rods, just noise and smoke and be down on power.

 

[GrinningGSer]

Your cheapest easiest thing to do next is drain and change the fuel.
GS911 ( find a friend ) for codes next
Everything else is guesswork
Hey I’ve had systems fail on my 1200 that needed diagnostic tools followed by expensive ‘replace and see if that fixes it’ ( which it didn’t ).
Some stuff is beyond an amateur and can get very expensive if you guess wrong.

 

[Santa-2512]

Dip a stick in the tank and drip some of the contents into your hand

if it evaporates and smells petroly = petrol

if its waxy and stinks like fuck = diesel

 

[timgib]

Hi just a follow up to my post, it seems I’ve got to an age where your mind plays tricks with yourself. After a cracking ABR festival & a near 140 mile return journey to the petroleum station. My head had a brain fart & even though I thought I read super unleaded on the petrol pump & upon checking the receipt with the service station I had as most suspected ( i was also starting to doubt myself) put in premium diesel! I use the station regularly to fill up my diesel car & whilst this isn’t an excuse I can only think as I was nearly home I slipped up for the first time in my life by not concentrating enough & it cost quite a few hours of work & a sleepless night or two.

What an idiot I felt but with the extremely valuable help from my brother in law who’s way more mechanical minded than me we have, well mostly him we eventually fixed my error. Thanks to everyone who came on here with there helpful suggestions, it’s appreciated.

 

[Santa-2512]

Hi just a follow up to my post, it seems I’ve got to an age where your mind plays tricks with yourself. After a cracking ABR festival & a near 140 mile return journey to the petroleum station. My head had a brain fart & even though I thought I read super unleaded on the petrol pump & upon checking the receipt with the service station I had as most suspected ( i was also starting to doubt myself) put in premium diesel! I use the station regularly to fill up my diesel car & whilst this isn’t an excuse I can only think as I was nearly home I slipped up for the first time in my life by not concentrating enough & it cost quite a few hours of work & a sleepless night or two.

What an idiot I felt but with the extremely valuable help from my brother in law who’s way more mechanical minded than me we have, well mostly him we eventually fixed my error. Thanks to everyone who came on here with there helpful suggestions, it’s appreciated.

Tommorow just pop your licence in the post back to DVLA

get the bikes & cars up for sale and get a pushbike , clearly this technology lark is getting to much for you

 

[Hartley]

Hi just a follow up to my post, it seems I’ve got to an age where your mind plays tricks with yourself. After a cracking ABR festival & a near 140 mile return journey to the petroleum station. My head had a brain fart & even though I thought I read super unleaded on the petrol pump & upon checking the receipt with the service station I had as most suspected ( i was also starting to doubt myself) put in premium diesel! I use the station regularly to fill up my diesel car & whilst this isn’t an excuse I can only think as I was nearly home I slipped up for the first time in my life by not concentrating enough & it cost quite a few hours of work & a sleepless night or two.

What an idiot I felt but with the extremely valuable help from my brother in law who’s way more mechanical minded than me we have, well mostly him we eventually fixed my error. Thanks to everyone who came on here with there helpful suggestions, it’s appreciated.

You aint the first, wont be the last. Glad youre sorted.

 

[Gavla04GS]

Hi just a follow up to my post, it seems I’ve got to an age where your mind plays tricks with yourself. After a cracking ABR festival & a near 140 mile return journey to the petroleum station. My head had a brain fart & even though I thought I read super unleaded on the petrol pump & upon checking the receipt with the service station I had as most suspected ( i was also starting to doubt myself) put in premium diesel! I use the station regularly to fill up my diesel car & whilst this isn’t an excuse I can only think as I was nearly home I slipped up for the first time in my life by not concentrating enough & it cost quite a few hours of work & a sleepless night or two.

What an idiot I felt but with the extremely valuable help from my brother in law who’s way more mechanical minded than me we have, well mostly him we eventually fixed my error. Thanks to everyone who came on here with there helpful suggestions, it’s appreciated.

To prove you're not alone....

I did it a year ago and @Eastmidsbiker quickly diagnosed the issue with the Shell V-Products both being red nozzles......

 

[timgib]

That’s my first time, but as I was looking on the internet for things that I could do to rectify my mishap I found a few others guilty of the same brain fart. It has been traumatic for me & im grateful for my brother in laws ability in doing the tasks needed. Thanks again for the reply’s

 

[timgib]

You aint the first, wont be the last. Glad youre sorted.

Thanks for that

 

[DJ123]

At least it proves the GS isn't a real tractor, as it didn't love running on the Diesel.

 

[Pukmeister]

Thanks for the honesty in your feedback, some folks would tell porkies or deny the error.its an honest mistake to make, especially when tired and/or in a rush to get home.

Good news is, other than the risk of “fuel dilution” to your oil making it wash the bores down a little, diesel itself is a pretty good lubricant and your engine should be fine, though I would consider changing your oil for longevity and peace of mind. Now you have cleaned out 99% of the diesel, after a few tanks of petrol have been through it, it will be like nothing ever happened.

If you put petrol into a diesel however, the damage is usually pretty catastrophic especially to the high pressure fuel injection pump.