diesel in 750s

[thekeyman 32]

a year ago , we had a fuel shortage in London (tanker strike l think) by mistake l added 5litres of diesel to two bars on the fuel gauge. rode about 1/4 mile before l realised but the bike ran up to then. drained the tank and filled with premium . it started ok and l have been running it since and the only change l noticed is the fuel range. the mileage appears to be 40 mpg in mainly inner city riding . is this acceptable or did l ruin a sensor with the diesel. l am not seeing any blue smoke, and it starts as well as before , is there any other reason, its done 45,000 miles on a 2015 bike. l guess l,ll have to take it on a long country ride to really check the mileage but most of you have said you get 70+ even in town. l,m 77 yrs of age, so no tearaway just know London traffic lights and make good times without breaking the law.

[Andy131 1,786]

Diesels use the fuel as a lubricant for things like the high pressure pump, putting petrol in a diesel tends to damage the bits that need the lubricating properties.  Doing it the other way around is usually safer, odds on when it finally got to pure diesel the engine cut out before any more damage could be done - don't think that diesel will ignite with a spark plug, then again diesel boilers do have spark ignition, but a much bigger spark.

 

I would have thought that you could have blinded the oxygen sensor with soot and that she might be running on default settings - could account for poor fuel economy, maybe cleaning it would help, but to be honest I would go for an OBDII read first, this should show live readings from the oxygen sensor and save you stripping her down and chasing "maybes" - fixing engines based on replacing parts that might or might not have failed is an expensive way to fault find.

 

Can't comment on fuel economy riding around London (or any other big city) as I tend to be of the opinion that if they don't want me on my bike then they don't want me to spend in the shops - there's always another shop somewhere mor friendly.

[Slowboy 24,726]

3 hours ago, Andy131 said:

….. - don't think that diesel will ignite with a spark plug, then again diesel boilers do have spark ignition, but a much bigger spark.

Honda Transalp 700’s can’t ignite diesel, apparently, just sayin…..😱

[Tegraman 3,508]

I thought NC 750 bikes were diesel 

[Andy m 26,943]

10 hours ago, Slowboy said:

Honda Transalp 700’s can’t ignite diesel, apparently, just sayin…..😱

Neither can a BMW K100 when the ripping Scottish nerks fit a green handle to the Diesel pump and have the siphon pipe under the counter all ready borrow so long as you dump the Diesel into their cans (no refund given) 🤬🤬🤬

 

I wouldn't have thought it would do any harm. Diesel just doesn't burn except under massive compression. It actually lubricates to some extent. If it's not burning it isn't causing soot. 

 

I'd be getting this bike out of the city for a day to see what it'll really do and riding it like the low revving Diesel-like engine it is. Usual checks first, tyre pressures, brake not binding, chain slack etc. 

 

Andy

[Slowboy 24,726]

A tank full of the stuff and a short run before the white smoke out of the exhaust showed it needed a rest didn’t hurt my Transalp at all. A complete drain and a forced start to drag the remainder out of the injectors was enough to see it running just fine. Carried on just fine for the next two years before I got bored with all that reliability and bought a Ducati…😁

Edited April 28 by Slowboy

[Dan German 2,226]

I would think fouled plugs or dirty O2 sensor would be the extent of damage. How much fuel has run through it since? Personally, I would start with running a good injector cleaning additive through at least one tankful, just to see if that improves it.

 

When I worked a used Mercedes dealer, we often had diesel cars come in on the hook having been inadvertently filled with petrol. We would drain the tank into a can, and use the diesel-tainted petrol in our big V8 Dodge truck that we used as a snow plow and general shop truck. It smoked a bit, but ran just fine. 

[EdG 359]

8 hours ago, Dan German said:

I would think fouled plugs or dirty O2 sensor would be the extent of damage. How much fuel has run through it since? Personally, I would start with running a good injector cleaning additive through at least one tankful, just to see if that improves it.

 

When I worked a used Mercedes dealer, we often had diesel cars come in on the hook having been inadvertently filled with petrol. We would drain the tank into a can, and use the diesel-tainted petrol in our big V8 Dodge truck that we used as a snow plow and general shop truck. It smoked a bit, but ran just fine. 

A few years ago I mistakenly filled my Diesel Golf Mk6 up with petrol.  I got 100 yards from the filling station before it went into limp mode.  Home was only a mile away and I slowly limped home.  The first problem was finding enough cans to empty the petrol/diesel mix into.  A friend donated a couple of old jerry cans to add to my own collection and I used a small electric pump to empty the tank.  I replaced the fuel filter, filled the filter with diesel and put a gallon of diesel into the empty tank.  I wound the engine up and away she went.  Still going strong with 95,000 miles on the clock.

I've not fortunately filled any of my bikes with diesel (yet!) but my brother put diesel in his BMW R76/6.  There was still some petrol in there, so he managed to get it to fire up.  I followed him home  (at a distance)  his path marked by a smoke screen.