Surely not...

[lingeringstin...]

Here’s some interesting carburetor waffle, not that anybody cares anymore. But that’s always the way- old technologies reach their working zenith at pretty much exactly the same time they become obsolete due to a NEW and IMPROVED method of doing the same thing.

For instance the recording and playback quality of cassette tape finally became CD quality, what with all that Dolby and other science thrown in, at pretty much the same time as CD’s became the new thing. I remember how after all the arseache of tape hiss and background noise I was finally, eventually, truly amazed at what could be done with an inexpensive cassette deck.

I skipped CD recording and went straight to digital multi tracking on a shitty laptop which was WAY easier to do. But it didn’t nullify the point that tape had, in it’s final days, finally achieved perfection for recording quality.

But I digress.

I’ve been using a petrol/diesel mix for fuel for some time now and over the years have had the opportunity to extensively play with mixture ratios and carb tweaks, and I’ve noticed something. There seems to be a certain Perfect Ratio where the mix has the best of both worlds, and just a very tiny shift one way or the other in the ratio makes a noticeable difference to the way my particular engine performs.

Bear in mind that my primitive two stroke MZ engine has pretty much ONE moving part and very little room for fancy performance tweaking, and my bastardized SU carb is basically nothing but an open air tube with an adjustable fuel leak where the mixture of fuel to air is adjusted by a flat bottom slide and a certain taper of needle. No other helper jets or airways of any kind. Not even an idle circuit.

I don’t have any idea what my compression is but I’ve experimented with it over the years and have tweaked it to a point that seems to work best, which as far as I can tell is a bit higher than it would be normally but not extreme at all.

And as for my homemade expansion chambers, well that’s gone all round the houses over the years to come back to basically bog standard MZ dimensions for best overall road use so that’s nothing much to consider.

So after years of riding and tweaking and thinking and stinking I have now come to the conclusion that on MY bike, with THAT compression and THAT carb set up THAT way, the perfect petrol to diesel ratio seems to be exactly 4.77 liters of petrol (bog standard unleaded) to one liter of diesel.

The strange thing is that if I alter that ration even slightly, such as only putting in 4.70 petrol or being a bit lax with my diesel measurements, I can actually notice the difference. Too much petrol in the mix thins the fuel which leads strangely to more smoke, less “lugging power" (the ability to stay in a gear for a wider range of speeds) and less mileage, and too much diesel leads to more smoke and the carb running lean which just does what a carb does that’s running too lean.

In the event of misjudging my fuel mixture I do have the ability to reach down and tweak my SU jet tube nut on the fly, which raises or lowers the jet tube in relation to the needle. That’s a sort of “get by” measure that means I’m in no danger of overheating the engine or of being stranded or something, but it’s not ideal. The best thing is to be very careful to hit exactly the 4.77/1 ratio (red diesel slightly different).

This gives the best performance on my bike, and the fuel economy drops considerably if I muck up this perfect ratio. There really does seem to be a perfect spot where if the mix is JUST right it performs way better than if it’s even slightly out. Perhaps there’s some rocket science as to why but all I know is THAT mix works for ME at THIS point in time under THESE conditions.

That may or may not be the case on any other two stroke contraption, but then again it MIGHT be. This could give a performance advantage for such applications where any size of two stroke engine in employed. Pause for thought and consider lawnmower racing, radio controlled aircraft, vintage bike racing, competition chainsaws, etc.

Now, I know the age of carbs is long past and nobody cares anymore. But I just thought you might want to keep that little bit of hard earned, long researched Secret Fuel Ratio alchemy in mind the next time you’re discussing random engine minutia with a dinosaur in a flat hat smoking a pipe round a camp stove.

Of course I’m sure the whole idea of liquid petroleum fuel will soon be old hat, but I for one am glad to have had the opportunity to dabble in Satan’s Piddle. Of course I’m certain that given half a chance treehuggers from the future would probably come back in a time machine to muck it all up, the bastards.

(ominous music plays, voiceover)

"On the evening of September 29, 1913, Rudolf Diesel boarded the post office steamer Dresden in Antwerp on his way to a meeting of the Consolidated Diesel Manufacturing company in London. He took dinner on board the ship and then retired to his cabin at about 10 p.m., leaving word to be called the next morning at 6:15 a.m.

In the morning his cabin was empty and his bed had not been slept in, although his nightshirt was neatly laid out and his watch had been left where it could be seen from the bed. His hat and overcoat were discovered neatly folded beneath the afterdeck railing.

Ten days later, the crew of the Dutch boat Coertsen came upon a corpse floating in the North Sea near Norway. The body was in such an advanced state of decomposition that it was unrecognizable, and they did not bring it aboard. Instead, the crew retrieved personal items (pill case, wallet, I.D. card, pocket knife, eyeglass case) from the clothing of the dead man, and returned the body to the sea.

On October 13, these items were identified by Rudolf's son, Eugen Diesel, as belonging to his father."

I’m saying nothing.

[Conzar]

Pardon?
____________________
Current ride: ZX6R 636 ------- Previous:KTM EXC 450 Supermoto --- ZX6R B1H --Hornet 600--CBR 600--SV650
11:05:35 Rob Fzs: i just wanna own an rd350 valve before they send us to war with durkadurkastan

[nowhere.elysium]

[goto10]

TL:DR - He got his bike running nicely.
____________________
'12 NC700S & '12 CB600F Hornet [Stolen by some dickless twat] Suzuki GT500 shed

[Rogerborg]

Sorry, zoned out, was he on about the Superdream being the bestest bike ever?
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[Shinigami]

meth - not even once
____________________
Current: Honda City Fly CLR125 2003 Honda CB600F Hornet 2008 Yamaha FZ6 S2 + 1991 Kawasaki GPZ500
"Once you realize what a joke everything is, being the Comedian is the only thing that makes sense.

[stinkwheel]

Good to see you and stinkybob are still alive and well.

I was thinking about both of you at the diesel bike rally last weekend. I'm sure you'd have had a great time arguing with the diesel lot about how your bike can't possibly work.

Are you still running it with urine injection? Did you find thge previous nights alcohol intake affected the stoichiometry?
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Nope.]

You are Teflon Mike and I claim my £5.
____________________
Former: Derbi GP1 50, Sachs XTC 125, Suzuki GSXR 400 GK73A, Kawasaki ZX7R, Suzuki DR250, Yamaha RD350
Current: 2011 Yamaha XT660Z Ténéré, 2003 Yamaha YZR-R1 5PW (In Build), 2009 Kawasaki ZZR1400

[The Shaggy D.A.]

[Rogerborg]

I dunno, he does LIKES his CAPS. But didn't mention the Benly once, so I guess that's conclusive.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[stinkwheel]

He's definately not Teflon Mike.

I recognise the SU carburettor in his avatar although I believe he was experimenting with a mixture of meths and BBQ lighting fluid at that point.

In fact, I have a photo of the bike it's fitted to.
https://i48.photobucket.com/albums/f216/stinkwheel/rat%20and%20survival%2007/01430011.jpg
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[nowhere.elysium]

[stevo as b4]

I'd like to know how well diesel fuel lubricates the piston and bore compared to a modern Ester based synthetic low ash oil though?

Do you get much carbon build up in the engine/exhaust compared to running 2stroke oil? And how much smoke does your bike make in comparison to say running 40:1 on 2stroke oil instead?

The diesel thing is very interesting, and it's got me thinking that if it's a very good lubricant, maybe this is another factor why diesel engines generally live a long time compared to similar sized petrol's?

[Jenks]

i remember his paint thinner tests!
Rex has really tryed running the mz on anything hes found.
____________________
1978 MZ TS 250 1 Supa 5
1992 yamaha fzr1000 exup
1998 aprilia af1 sintesi

[Rogerborg]

Is he taste-testing the stuff first?
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[Timmeh]

One day rex will perfect an engine that runs on tippex, paint stripper and menstrual fluid. Then we shall remember the day that petrol ran out and he became master blaster.
____________________
GSXR400 x2 | '94 RVF400 | '93 TZR125 4DL (again)
20:22:30 BLUEX5: i would love to be forced to undergo a**l plugging with different sizes
20:48:18 Temeluchus: comp you hunk of smouldering homos3x you

[merquis00]

[lingeringstin...]

[quote="stevo as b4"]I'd like to know how well diesel fuel lubricates the piston and bore compared to a modern Ester based synthetic low ash oil though?

Do you get much carbon build up in the engine/exhaust compared to running 2stroke oil? And how much smoke does your bike make in comparison to say running 40:1 on 2stroke oil instead?

The diesel thing is very interesting, and it's got me thinking that if it's a very good lubricant, maybe this is another factor why diesel engines generally live a long time compared to similar sized petrol's?[/quote]





I've found that running diesel keeps the the engine far cleaner than when I ran two stroke oil, even the good stuff. There's far less carbon buildup on the piston and in the exhaust.

I used to have to burn out my exhaust with an oxy acetylene torch every few years to get rid of the carbon buildup in the expansion chamber and much more often out of my baffle, and now running diesel in the mix it seems to stay amazingly carbon free for a long time.

As far as I can tell there's been no difference in the lifetime between engine rebuilds either. I think modern diesel has a lot of extra shite in it that cleans and stops ash etc.

The only downside I've found is that whatever weird chemicals there are in modern diesel it eats certain things like rubber seals and plastics. Had be aware of what lies between petrol tank and exhaust, which thankfully on my bike isn't much.

I now have to be sure to use diesel friendly main seals like viton or something. Luckily diesel doesn't melt my fuel bowl plastic float or eat my fuel line but I did used to run a plastic tap from a beer brewing kit as an inline fuel tap which worked fine with petrol but diesel ate them up in about two weeks time so had to change to brass. My fuel filter is a diesel one.

Basically there seems to be a lot of benefit to using diesel instead of two stroke oil. Seems to give a better kick to the combustion as well. I'm getting better performance and mileage now.

[G]

From what I can, it's concluded that when people move on to a new technology, the old technology which is no longer being worked upon isn't improved any more, is at it's "peak".

Not sure that actually needed pointing out?

[Shaft]

[Rogerborg]

Electric vehicles, for one.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[MarJay]

Please don't use caps like Tef does. Please don't write like tef does.

Welcome to the forum. Tentatively.

Can I just add that Audiocassettes have never and will never approach CD quality. CD's are the last true high quality uncompressed digital format. They will be better quality than anything we have in the future, and they are better quality than anything we have had in the past.

Pardon the digression.
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Pete.]

Sorry, but anyone who uses 'but I digress' as a standalone paragraph sets alarm bells ringing right from the off.

Apart from that, who would be surprised that changing the mix ratio by a measly 17% would have an effect on how it runs? And as for red diesel running different to white, well - LOL.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[stinkwheel]

The usual laws of physics and engineering do not apply to stinkybob.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[lingeringstin...]

[quote="Shinigami"]meth - not even once[/quote]

Purple meths to be exact, like what you buy at B&Q. Ran well on that but I discovered that it only temporarily mixes with petrol if it's all agitated together. The meths contains a bit of water in it.

You can pour the meths in the tank with the petrol and shake it up a bit and it'll work, but if you let the bike sit for a while it separates out so you get a blob of water in the bottom of the fuel bowl. You CAN just shake the bike vigorously to remix it but this starting procedure gets really old really fast.

I then used an old two stroke oil injector to inject the meths straight into the crankcase via the existing two stroke oilways I'd previously blocked off and that worked much better. You could start the bike as normal and the meths just got spat into the crankcase as you rode.

It did make a nice performance difference but I never really went far enough with that experimentation. As I recall the meths was a bit too expensive to run on a regular basis and you had to rejigger the jetting to use it