Diesel fuel in r1200gs tank

Hi all,

A friend of mine put, accidentally, diesel fuel in the tank of his 1200gs, 2004.
He started the bike and it quit after ~ a few seconds, normally. Then he drained the tank and put normal gas. The bike started and was ride-able.

The next day, it started to run bad. If you twist the throttle, it would sputter, as if the red line rev limiter was at 2500 rpm.

The first thing to do was clean the tank on the inside and replace the fuel pump. I also cleaned the injectors in a ultrasonic cleaning shop. Lucky him, I had a R1150 R Rockster pump around and it is a direct swap. I put in fresh fuel and started it. Nothing changed, the bike runs the same.

So I am thinking it is the fuel pressure regulator fault. I ordered one and am now waiting for it to arrive. I am asking myself if it is worth the trouble to fit a 3 bar FPR instead of the usual 3.5 bar FPR that the 1200 comes fitted with. Replacing it is a PITA!

Also, do any of you think I should be replacing anything else? IMHO, the bike now acts like it is the FPR's fault. I never opened one, but I guess it has a seal and a spring inside and the seal went bad as it is not designed for diesel, but for gas.

Dan.

I would guess to clean out the fuel tank. fuel filter, fuel lines and fuel pump would be enough.

Have you tried to connect a fuel line from a separate fuel tank directly to the fuel pump?

My answers inline.

Dan.

That's usually 'mostly harmless', it's petrol in a diesel engine that gets expensive.

I'd guess plugs are fouled and everything is a bit carboned up. Pull one of the plugs to check and replace or clean them if they are fouled and try again.

Pete

A friend of mine accidentally put a couple of gallons of diesel in his K75. After he realized what happened he stopped at every gas station along I-5 and topped op with real gas which diluted the diesel. After the bike ran normally he did not do a damn thing. He still has the bike a couple of years later. Ever heard the expression "if it ain't broke don't fix it." Dave

Forgot to mention, the owner also changed all 4 spark plugs back then.

Dan.

Yep the plugs are probably oiled so I would clean or replace them.

But the bike is not rideable right now. You cannot overtake even at low speeds. When it needs more fuel - higher rpms, the engine does not work right.

Mix some Seafoam and Heat in with the gas and rev the throttle for five or ten minutes. I had a full tank of bad gas in my RT this Spring and it would not even start until I put in the Safoam and Heat and sprayed ether in the intake. Once started it coughed and stuttered for about five minutes and then ran fine

I suspect one of the primary coils has picked this occasion to fail, it's old enough for it to happen. Did the bike get wet or was it washed around the time diesel was introduced? I think my first coil went out on my 05 r12gs around 100k, and it died right after a rare pressure wash.

If diluted ...it sounds like a situation similar to adding snake oil (Marvel Mystery) to gas for upper cyl lubrication ...

Could it be that the O2 (lambda) sensor stopped working after having been drenched in diesel and then, after being started on gasoline, having that same diesel burnt in?

I believe Roger 04 RT, had a post on how to check the function of the O2 sensor, at least enough graphs to see how a working sensor should behave.

Maybe start with disconnecting the sensor an do a Motronic reset? Should still run like crap in "limp home mode", but differently from now - if the O2 sensor is the problem.

/Urban

"A friend of mine put, accidentally, diesel fuel in the tank of his 1200gs, 2004."

I should remember this one, referring to myself in the 3rd person.

Check out this "Bad Gas" thread in the Rocky Mountain regional forum. Apparently there was a gas station in the mountains that had a diesel/gas mixup when there underground tanks got refilled and some ADV members posted up the effect on their bikes.

http://advrider.com/forums/showthread.php?t=992837

Without reading through the whole thing, here is the post from one of those affected:

"Just picked up my very nicely running FJR! Dealership removed the fuel tank, drained & flushed it. Flushed & cleaned fuel injection system. Installed new fuel filter & 4 plugs! Compression test on all four Cylinders came back perfect. She's nice & crisp again!"

Good luck getting things running smoothly again.

Two years ago, I put diesel in a rented 800 in Poland. Had it taken to a dealer where they drained the fuel, PUT IN NEW PLUGS, and I was back on the road in 3 hours, even with language barrier.

I seem to remember another post about a poorly running bike. IIRC it turned out to be the low voltage connections to the stick coils hadn't been connected properly.

You mean, they don't speak Gaelic in Poland? Of all the...I'm cancelling my trip there.

I changed the FPR this evening, with no luck... The bike runs the same.

I took out one upper spark plug and it is white, so the mixture is too lean, so not enough fuel.

The next thing I am thinking about is replacing the hoses. Perhaps the diesel fuel made the inside of the hoses to melt, preventing the needed fuel volume to get to the injectors.

Sadly, I do not have tools to measure fuel pressure.

Dan.

Diesel fuel is not going to damage hoses.

Oh BTW change the spark plugs. I'm not saying it'll fix it but by leaving them in you're by-passing a likely culprit. I've seen many cases when a plug that looked good didn't work correctly. It was alway after a fuel related issue. The worst you could do is have fresh plugs before throwing expensive parts at it.