Fuel Consumption Figures

[alexanderfoti]

I have been tracking my fuel economy from day one, figures here:......

I assume my lower numbers than most is due to my mostly 100% town riding, and use of Veg instead of diesel

What percent of the RUG you use is alcohol?

Standard Shell UK petrol so 5% ethanol I think.

[albertaphil]

The way I ride around here which is all highway at 100kmh or as close to that as I can get depending on the wind, had given me a low of 89mpg and a high of 92.5mpg over the last 1250km. This is with my 650cc ruggerini twin in a superdream.

It seems a far cry from what most of you others are getting. Particularly compared to Ian's 136mpg out of a bigger version of my engine at the same speed.

I have never run a tank at 90kmh but I think 100+mpg would be feasible. That is still a long way from 136mpg or even ~115mpg like alex.

Do you think a windshield would help?

[Anorak_ian]

The way I ride around here which is all highway at 100kmh or as close to that as I can get depending on the wind, had given me a low of 89mpg and a high of 92.5mpg over the last 1250km. This is with my 650cc ruggerini twin in a superdream.

It seems a far cry from what most of you others are getting. Particularly compared to Ian's 136mpg out of a bigger version of my engine at the same speed.

I have never run a tank at 90kmh but I think 100+mpg would be feasible. That is still a long way from 136mpg or even ~115mpg like alex.

Do you think a windshield would help?

Are you reving to top revs in top gear?
If so your gearbox isn't wide enough (for best mpg).
My engine revs to 4000rpm+ but only to 3400 - 3500 ish in top gear. The closer you ride to 2300rpm (fuel curve) the better the mpg. 2300rpm isn't going to be very responsive in top gear though. Crawl to top speed or suffer high mpg, you need to find a happy medium.
Of course, the power to weight ratio is very important, I'm about to dump 16+kg from my bike. I have a plan

[coachgeo]

...Do you think a windshield would help?

Ian has some good points about power curve but to answer your question... yes windshiled may help. More slipery you can get the air around you the better... butt... not sure if that matters much below 50mph? Read up on some of the home built bicycles and or motorcycles with fairings etc. to improve MPG. They may have some data in their blog/build about when speed really starts to make a huge difference.

[Anorak_ian]

I have just taken a look at your engines fuel efficiency, it isn't good.
It's the exact same as the MD191 850cc and RD270 1205cc engines.

The RD270 is 30hp @3600 and should rev to 4000+ a very desirable engine.

[alexanderfoti]

The RD270 is 30hp @3600 and should rev to 4000+ a very desirable engine.

Especially if it does 92mpg for 30hp!

[alexanderfoti]

The final gear rev ratio I think is an important one.

On mine its 50mph at 3200 RPM. With a redline at 3600 @ 55mph. Its most fuel efficient at 2800 rpm which is about 40 mph, so with my town driving in constantly crossing that efficiency line. If I did more driving at 40 mph steady, I would suspect MPG would jump to 150-160mpg.

Im not sure about fuelling on yours, but it is adjustable, its not overfuelling is it? Mine is still slightly overfuelling, but I suspect thats due to incomplete burn of WVO, as if i adjust for slightly less smoke, my power drops off.

[Anorak_ian]

The RD270 is 30hp @3600 and should rev to 4000+ a very desirable engine.

Especially if it does 92mpg for 30hp!

Mpg will be the same as his existing engine, but if he gears it up he will get real benefits.

[alexanderfoti]

The RD270 is 30hp @3600 and should rev to 4000+ a very desirable engine.

Especially if it does 92mpg for 30hp!

Mpg will be the same as his existing engine, but if he gears it up he will get real benefits.

Exactly my point.

[albertaphil]

According to my ruggerini manual the md191 gets best bsfc at 2500rpm of 245g/kw/hr. My md151 is slightly worse at 260g/kw/hr at 3000rpm. I can run at 100kmh at 3300rpm in 5th gear or 2800rpm in 6th gear. I can pull 6th gear on the level our up slight hills with no wind. Anything more and I don't have the power unless I shift down.

If we assume that it takes 12hp to run at 100kmh which I think is pretty accurate then the md191 should be capable of 111.6mpg if geared ideally. An ideally geared md151 would be capable of 108.3mpg. With my 6 gears I'm pretty close to ideal gearing.

I have a restrictive exhaust and intake which might make some difference when I get that fixed. As for fueling, I make enough smoke under full fuel for an observer to know I'm a diesel but I'm not wasting much fuel as smoke. If you go to the media category to find links to some videos of mine.

I do much of my riding with one of my sons giving us a total weight of machine and passenger of around 675lbs.

Most of my riding is with maximum acceleration but with horsepower numbers as low as many of US have you cant really operate with anything less.

[Anorak_ian]

Your right about those fuel figures and revs, who would have thought they would have been so different as they are from the same stable (I guess I should have taken a look). I wish my engine's sweet spot was 3000rpm.

Sounds like you have everything sussed out.
My exhausts were chocking the engine and it behaved like a real pig.
A bigger bore, longer silencers and less baffling, what a difference to the ride.

[alexanderfoti]

I have a nice long intake on mine so as to keep it quiet and my exhaust is just a straight pipe.

I have a lot of extra weight on mine and a top box as well which probably affects economy. I still think they are pretty good on fuel. If their fuelling was a bit more advanced though they would push 160+ I think without issue.

[albertaphil]

My intake pipe is about 15" long and corrugated. And my exhaust, while unmuffled was built out of one of the original Honda twin wall pipes cut and rewelded poorly at angles. I know my some had to escape through a couple of joints that maybe have an area of 1 square inch. Probably part of my problem...

[Anorak_ian]

I think you have pinpointed the problem.
Bigger diameter pipes may be an advantage, specially if it is 2 into 1.

I know that a convoluted hose mixes the air around, but I'm not convinced to the benefits, as there are swirling vanes in Ruggerini cylinder heads.

[John]

[quote="alexanderfoti"]It's my thought that I have to run my bike on veg for it to be worth it. Especially if a scooter that is faster is doing 163mpg!!!

What isn't mentioned about the admirably economical Honda Innova 125 though, Alexander, is that while it is undeniably faster & more accellerative than the 150lb heavier Yanclone Enfield, - it's famed 163 mpg is quoted by Honda themselves at a mere 45 km/hr, - or 27 mph. Any correctly set up diesel bullet could handsomely exceed that at those speeds by a HUGE margin. I would expect 210 mpg from my bike at that modest trickle. It IS a great compromise bike between superb economy & reasonably high commute speeds, but its great economy is relative.
At speeds of 45 - 50 mph, you would be unlikely to see much better than 120 mpg, which is still very good of course.
I have a yanclone 406 bullet fitted with the same 16T sprocket as the 350 petrol. This gives 52 mph @ 3600 by gps. For economy, I cruise at 36 mph by gps, which is 2500 rpm. (torque peak) On the route I take, at this cruising speed, my overall average speed over 500 miles works out at 33 mph.
It averages 182 mpg. Which drops to 160 mpg at a 40 mph cruise/ 36 mph average.
The sprung fuelling screw is now wound in to touch the governor arm at idle, which is the recommended position at rest by Yanmar. It's impossible to persuade the engine down to that setting with even a 17, let alone an 18 or 19T. It wouldn't pull any of them.
But it is still slightly too highly geared with a 16 now the engine fuelling is correct, since it is producing less torque & can no longer pull the 16T out to 52 & 3600. The oversquare 406 likes to rev, it hates slogging at low revs with ambitious gearing. It smooths out beautifully once clear of 2700 rpm, which is where the injection timing is set up to be most favourable. With a 15 sprocket, (48.6 mph @ 3600 by gps) - at 35, I would fully expect to see 190 mpg plus without actually trying for economy.
With the fuel screw where it should be, the engine is now smokeless, & producing a mere 8.4 bhp as per spec. So a genuine 45 mph maximum cruise speed @ 3336 rpm, is as much as you could reasonably expect from such a low power engine in a bike & rider weighing 600 lbs.

[Diesel Dave]

I regularly got 140 mpg on an old Innova carb model; biggest problem is the titchy 3 litre tank, also the last bar on the LCD fuel gauge starts flashing but you have no idea when it started.

I doubt the motor would last more then 45,000miles even with careful ownership. Tyres shred in 5k miles and chains not more than 10k.

My diesel enfield is waaaaay past 150,000 miles, tyres last 33k miles, chains the same. It also has loads more road presence; just the sound alone keeps cars at bay.

[alexanderfoti]

My new Kubota D850 based Superdream is running 82.3mpg over 957.7 miles.

I have lost a fair bit of fuel between fills due to fuel filter changes, tank removal and tap leaks.

Will see what changes come from the servo driven throttle and a full tank full of non leaking fuel

To compare, My NC700X DCT has averaged 64.45mpg over 3240 miles.

[UAofE]

If we assume that it takes 12hp to run at 100kmh which I think is pretty accurate

45mph for my Kubota can be maintained even with moderate hills, 50mph can be maintained on level ground and I have touched 60mph a few times with favorable wind.
Right now its geared for 70mph@3600rpm. I'm planning on installing the turbo this week so we will see how it contributes to top speed.
If I were to gear down from 15 to 14 tooth drive sprocket today I'd bet I could get it above 60mph.

[alexanderfoti]

Will be interesting to see the effect the turbo has on FE.

It has been said to me, that If I leave the fueling alone, a turbo will increase efficiency.

[gilburton]

Taking the figures from that table 96mpg (US) translates to app 115 MPG (UK)