Had an older guy (~75yrs) come to buy some parts, he turned up driving an S800 Honda (car) and showed me photos of his ~15 bike collection..lots of oldies, Gold Star, Triumph and the like, couple of Ducati singles, a 900 desmo race bike and his current project 996. We were talking about upkeep and leaving bikes standing for a while and then the nature of modern fuels. It turns out he puts up to 10% diesel in with his petrol and swore it was a good thing to do for lubrification etc... I can't seem to find anything that refutes or confirms his point. Can anyone shed light?
I don't see how they'd run, if that's what he's talking about.* But a guy I knew, long ago, who among other things painted and welded fuel tanks, after draining the petrol, put diesel in, which pushed the rest of the petrol fumes out. I would guess that putting diesel in for storage would be beneficial, eg in less rusting. *By which I mean you'd almost certainly have to change timings and jetting. When I was a novice I put meths in my tank (the violet stuff) and saw no difference but found it accumulating in the float bowl. And when much later I put avgas in the Bonneville, it popped and banged, despite those motors being designed for 5 star. It was a marginal improvement once I rejetted it, but still better on four.
Diesel in the petrol will reduce performance, and may well damage a modern highly tuned engine. If there were a benefit, Shell & Co would be selling it to us for a higher price, premixed, as their latest great idea. I've heard that back in the day, in super cold places, people choose to put a little petrol in the diesel to reduce the gelling effect of temperature. As petrol is a solvent that may work but it also removes some of the lube for the engine... Maybe old diesels weren't so susceptible to problems afterall they weren't fitted with hi comp motors & turbos then? Personally I've no idea, and I certainly wouldn't do it unless I needed to escape certain death from a Polar bear or something!
There's nothing really magic about diesel oil - it's just a tightly-specified light oil. The above would be a lot like a 2-stroke mixture that many an old bike & car engine managed to work very well on. Compression ratio for diesel engines is way more than all petrol bike engines (even 'high-performance' engines are only ~14:1) so the diesel oil won't make the engine 'diesel'... Yes - modern electronic sensors might gum up, etc but I'd say your old bloke knows what he's doing.
Yes perhaps a big penguin could do some damage with its beak? I don't think they chase people so if you leave them alone its probably OK? Unlike the bloody Polar bear!
Do you thing burning the oil would clog up the bike though? Would you put diesel in yours if you were storing it?
Probably not with an injected bike, but maybe 10%-ish is a bit much and it'd smoke a bit. My old Seagull 4hp 2-stroke outboard was something like 16:1 mix (so about 6%) and it never fouled a plug, but it did leave an oil slick behind it Food for thought I'd say...
Great little engines those Seagulls -I had one too. Took me & the boys up and down the river Hamble endlessly.
A little, sure. Like STP and Redex and so on. But enough and it'd alter the characteristics the engine was designed for. Octane rating. Flame speed.
Bears are already mean AF. I can't imagine how much worse it would be if the bear had a cactus stuffed up its ass.
Old time hack used to be to add 10% petrol into a diesel tank in winter. Can see more harm than good adding diesel to petrol. However, if it works for him then leave him to it. Personally, I would not copy. I used to run my diesel 4x4 on a 50/50 mix of veg oil/diesel. That was when you could get veg oil for 18p per litre.
old veg oil. heard and seen that, but not in a long time and deffo not on diesels with high pressure common rail's, EGR's, oxygen sensors, cats and DPF's. maybe an old carb model. maybe. i cant think of a quicker way of reducing the efficiency of a modern petrol than firing in any light oil. modern oils are not what they were back in the day. and you can ram yer generic cover all oils too. vehicle specific or it doesn't happen in my place.
I’ve heard of people doing it but I never have. I sometimes spray the inside of the tank with Gt85 if it very low on petrol just to coat the inside for storage.
Castrol R (castor oil) - just a spoonful in a tank of petrol makes the odour of the exhaust gases more pleasant.
Done it the other way round. Putting a litre of petrol in a tankful of diesel to run hotter and clean the dpf. Ran my old Grand Vitara for years like that though apparently parafin or high grade 2 stroke oil is better.
I've been told by several mechanics about the damage modern fuel can have on older bikes and they recommend that before I store my bikes (even if it's more than a couple months), I drain the fuel tank then use a 'storage fuel' like "Aspen" which doesn't contain harmful ethanol. It is expensive fuel, but you don't need much in the tank, just run the bike on the storage fuel before laying it up. I haven't had any problems yet (touch wood)... https://aspenfuel.co.uk/products/aspen-4/
