Heron V7 vs Hemi V9 MPG

[omega1987]

Hello all,

I'm very interested in getting a V9 in the future if Guzzi ever turn it into a 'standard' style bike with a decent fuel tank (20+ litres).

The appeal for me is the improved gearbox and increased power/torque but as I do about 350miles per week, fuel economy is also a factor and I know the Heron head design is supposed to offer efficient combustion with good fuel economy over the conventional Hemi head and obviously the larger volumetric capacity may also compromise economy but that said the new bike has taller gearing than my Breva and I'm wondering if it also has other efficiency improving design features like low friction coatings and improved fuel injection.

So do you think the V9 will be capable of MPG rivalling my 11 year old Breva?

[mtiberio]

tests indicated 57 mpg while flogged

[omega1987]

tests indicated 57 mpg while flogged

That's interesting, was that a low mileage V9?

I don't entirely trust MPG gauge's as my dads Civic is usually miles out but then again my Citroen C5's mpg gauge is usually spot on.

[rocker59]

  I know the Heron head design is supposed to offer efficient combustion with good fuel economy over the conventional Hemi head 

I don't know that.  I've owned two V7s and they return high 40s MPG.  Not real efficient, considering other bigger displacement / more powerful machines return as good or better fuel economy.

Heron is chosen for economy at production.  Not economy in use.

[omega1987]

I don't know that.  I've owned two V7s and they return high 40s MPG.  Not real efficient, considering other bigger displacement / more powerful machines return as good or better fuel economy.

Heron is chosen for economy at production.  Not economy in use.

I think the 750 small block does very well when you consider the less efficient shaft drive and air cooling (both of which I see as advantages for high mileage easy to maintain bikes).

A quick look on fuelly.com (see signature) suggests these bikes achieve similar MPG to chain driven middle weigh twins like the SV650 & ER650 whilst offering superior MPG to other shaft driven bikes like Honda's NTV650/700.

[Kev m]

I don't know that.  I've owned two V7s and they return high 40s MPG.  Not real efficient, considering other bigger displacement / more powerful machines return as good or better fuel economy.

Heron is chosen for economy at production.  Not economy in use.

Anecdotal and not saying Heron is in and of itself more or less efficient.

BUT, I have consistently gotten better fuel mileage (sometimes significantly) on my V7 than I have on any of my bigger/more powerful Guzzis, BMWs, Harleys.

Now part of that is size and power I'm sure.

But I typically get/got around 40 mpg on my 1200 Sporty, 1100 Jackal, 1100 Breva, BMW 1100RS etc. with an occasional spike in the mid 40s, and never 50 mpg unless once in a LONG while at high altitude.

I would get mid-40s typically on my 883s

I've gotten mid-to-high 40's on the Duc, maybe I got 50 once.

The absolute LOWEST I've gotten on my V7 was 45, but I usually get 50, the highest I've gotten was about 55 and THAT wasn't at altitude.

Now any of those bikes that Jenn has ridden any distance she would get higher - like always mid-to-high 50s on the 1200, 50+ on the 883, and she regularly gets 50-55 on her Duc.

What's my take-away from this.

Size and power definitely plays a role.

As does the rider (size and right wrist).

But in that limited comparison my V7 has definitely been the most efficient bike I've owned in recent history.

That said, I'd could probably match that from the Duc if I didn't use my right wrist so much when I'm on it. And looking at that the Duc has a slight weight advantage over the V7, and right wrist discipline would take away the power advantage.

Conclusion - I dunno... the V7 is pretty darn efficient?

[rocker59]

My 883 returned 50-55 regularly.

My Sport 1100 returns mid-40s.  If I ride my V7 at the same pace on the same roads, the fuel economy is about the same.

If a V7 is considered efficient, it's not because of its combustion chamber, but its displacement, tuning, and weight.

[Kev m]

My 883 returned 50-55 regularly.

My Sport 1100 returns mid-40s.  If I ride my V7 at the same pace on the same roads, the fuel economy is about the same.

If a V7 is considered efficient, it's not because of its combustion chamber, but its displacement, tuning, and weight.

Are you smaller and lighter than me? Cause that's part of how I might account for the 883.

I'd also say it was a much older model which was both lighter and less powerful than the current ones.

But if I rode my V7 on the same roads in the same manner as my Jackal/Breva (and I did regularly before moving to NJ) I got better mileage on the V7.

<shrugs>

[pikipiki]

I think the heron head was an efficient design in its day and the dished piston crown probably assisted in getting a good fuel air mix around the plug on carburettored bikes. but fuel injection with 2 valve hemi is best for economy if theres no variable valve timing which assists econommy with 4v head. Water cooling in its self does not increase economy but it facilitates efficient EGR which does.
A carefully controlled engine temperature and controlled EGR are required to reduce NOx emissions to Euro 6 levels which is why Air cooling has a limitted future.

[pete roper]

It will also depend on how shitty the original map is. Going from past experience I'll bet London to a Brick that it will be pretty drac. Most previous factory maps are sloppy rich and depend on the NB lambda input to trim the fuel back crudely to meet emissions targets. Once out of CL the maps remain hideously rich because the factory knows the first thing pencilnecks do is put on stupid loud pipes and they don't want to have to deal with the whining when pistons start melting! It's not exactly brilliant for fuel economy and engine life but it keeps the retards happy.

Pete

[Antietam Classic Cycle]

Not all Heron heads are created equal. Morinis return some pretty respectable mpg even when flogged. Yes, some of it is due to them being small (displacement) and light, but not all of it. Lambertini did a much better job in their design than Tonti did for Guzzi. My '80 500 Strada would regularly get in the low 60s, my first 350 K2 averaged upper 70s and once got 82. My current K2 is averaging 74 mpg.

[lucydad]

Good thread.

My 2012 V7R returns around 43-45 miles/gallon no matter how hard I flog it. Cruising in fifth gear at 70 mph the bike gets up to 48, maybe 50 miles/gallon?

By contrast, my Triumph 675 Triple STRX:  as calculated by its computer returns an average of barely 40 miles/gallon.  If I am really hustling, I know mileage has been into the mid thirties.  Three thirsty cylinders above 8000 rpm...

V9 tank is big enough.  Every hundred miles it is time to stop and have a break anyway.

[v65tt]

remember the later v7-II have the same 6 speed box as the v9 and run much lower rpm  that the 5speed box bikes when in top


My V7TT returns high 40's on trail tyres and oddly is more economical if the revs are kept over 4000rpm

[SmithSwede]

I've had the same experience as Lucydad.  With the exception of the V7 Stone, every bike I've owned showed significantly better fuel mileage if I rode it gently versus flogging it. 

But I always get about 42 to 45 mpg on the Stone, now matter how I ride it. 

So I stopped worried about fuel mileage and just ride the thing the way I want.   

[SmithSwede]

I also think "miles per gallon" is a potentially misleading metric.   Once you get into higher mpg numbers, there isn't much practical difference.  A better metric would be $ per year. 

Suppose you do 17,500 miles per year and gas is $2/gal.  An "efficient" 50 mpg machine will only save you $175 per year compared to a "gas guzzling" 40 mpg machine. 

From a purely financial perspective, it won't make sense to buy a new bike just to save $175 per year. 

In my view, what matters for high mileage running costs are things like tires and overall reliability.   

If you have a single $525 repair problem with the 50 mpg bike, that wipes out 3 years of fuel savings. 

One of my other bikes is a BMW F800S.  It consistently delivers excellent mpg.  But it's not cheaper to run than my Stone---because there's always some $300 or $500 surprise that wipes out the savings.

[omega1987]

I also think "miles per gallon" is a potentially misleading metric.   Once you get into higher mpg numbers, there isn't much practical difference.  A better metric would be $ per year. 

Suppose you do 17,500 miles per year and gas is $2/gal.  An "efficient" 50 mpg machine will only save you $175 per year compared to a "gas guzzling" 40 mpg machine. 

From a purely financial perspective, it won't make sense to buy a new bike just to save $175 per year. 

In my view, what matters for high mileage running costs are things like tires and overall reliability.   

If you have a single $525 repair problem with the 50 mpg bike, that wipes out 3 years of fuel savings. 

One of my other bikes is a BMW F800S.  It consistently delivers excellent mpg.  But it's not cheaper to run than my Stone---because there's always some $300 or $500 surprise that wipes out the savings.

I envy you guys sometimes. Here in the UK the 50 MPG bike would cost £1,730 to run over 17500 miles vs the 40mpg bike's £2,162 at current prices (£1.089 per litre). £432 would be a significant saving for someone like myself.

Just remembered that your MPG is different to mine
40mpg = 48 UK mpg, £1802 over 17500 mi
50mpg = 60 UK mpg, £1441 over 17500 mi
Still a £361 saving ($523).

[bpreynolds]

I also think "miles per gallon" is a potentially misleading metric.   Once you get into higher mpg numbers, there isn't much practical difference.  A better metric would be $ per year. 

Suppose you do 17,500 miles per year and gas is $2/gal.  An "efficient" 50 mpg machine will only save you $175 per year compared to a "gas guzzling" 40 mpg machine. 

From a purely financial perspective, it won't make sense to buy a new bike just to save $175 per year. 

In my view, what matters for high mileage running costs are things like tires and overall reliability.   

If you have a single $525 repair problem with the 50 mpg bike, that wipes out 3 years of fuel savings. 

One of my other bikes is a BMW F800S.  It consistently delivers excellent mpg.  But it's not cheaper to run than my Stone---because there's always some $300 or $500 surprise that wipes out the savings.

Thank you.  This is an excellent post and point.  You know, I don't think I ever really did the math on this.  Of course, the dollars saved are not the only thing I appreciate about an efficient machine, but still your post does put it in some perspective at least in terms of bucks.

[sign216]

One of my other bikes is a BMW F800S.  It consistently delivers excellent mpg.  But it's not cheaper to run than my Stone---because there's always some $300 or $500 surprise that wipes out the savings.

I hear that.  WTF is up with the modern BMWs?!  I was a loyal airhead owner until the modern BMWs made me switch to Guzzi.
Guzzis are a little old style, but that is the best, if you want to do your own servicing.

[steamdriven NZ]

When my Monza was a 500 it regularly did 55mpg regardless of load on board, pulling 5100 at 100kmh. With the 750 engine in it it now sits at 3600 at 100 and easily does 62mpg.
That's UK gallon measure of course, the full sized colonial measure being bigger of course than the US gallon.
Anyway, that's what I get, FWIW. 

[Arizona Wayne]

I typically get 50 mpg on my 750 Breva riding 65-70 mph.  On my MuZ 660 single I can get 65 mpg doing the same.  Sometimes I've gotten 65 mpg on my CX100 949cc Guzzi twin too, but usually 55 mpg.  I got 40-45 mpg on my LeMans IV.