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gman098

Would this MPG worry anyone here?

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 Long time reader, first time writer - good to be here 🙂

 

I picked up my stock 07 VFR in November and always experienced pretty poor fuel economy: city driving 75%, twisties 25%, I tended to get about 28MPG (UK, maybe 23 US). Since modding (PCV with stock tune, snorkel/flapper/PAIR, GPR pipes) , economy improved slightly to about 32 (~26 US) although I wouldn't have expected it to. This comes to about 120 miles on a full tank. If I do a tour and stick to 70MPH religiously, this goes to about 49 (~40 US)/180 miles.

 

Are these economy numbers worth worrying about? Opinion on other topics seems split on "good" MPG values. Otherwise, the bike runs like a dream and I bought in full knowledge she would be thirsty, but having always been in this condition, I don't have anything to compare to! In Feb I gave it a full service with new air filter, made sure everything was tight, replaced some cracked vacuum tubes, new tyres and chain/sprockets... Bike has 25k miles and is on original sparks; they look slightly worn but not too dirty and with sharp electrode tips, although this is my first experience of iridiums. FPR isn't leaking. It comes to temp quickly and runs at normal temp (<104.C) so I believe the thermostat is fine. It's hard to start maybe 10% of the time and the always exhaust smells rich, so possibly a starter valve synch is on the cards, or otherwise getting a professional remap? 

 

Any advice will be greatly appreciated 🙂

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Seems to be a bit low IMO, but I'm riding a '99 so it will be different. If I ride mine hard it will drop into the low to mid 30's mpg. I

honestly can't imagine riding hard enough to drop into the low 20's mpg., unless maybe I was riding a track day. But with the V-tech

I suppose revving it up where the V-tech operates all the time may result in lower mileage.

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 Long time reader, first time writer - good to be here

 

I picked up my stock 07 VFR in November and always experienced pretty poor fuel economy: city driving 75%, twisties 25%, I tended to get about 28MPG (UK, maybe 23 US). Since modding (PCV with stock tune, snorkel/flapper/PAIR, GPR pipes) , economy improved slightly to about 32 (~26 US) although I wouldn't have expected it to. This comes to about 120 miles on a full tank. If I do a tour and stick to 70MPH religiously, this goes to about 49 (~40 US)/180 miles.

 

Are these economy numbers worth worrying about? Opinion on other topics seems split on "good" MPG values. Otherwise, the bike runs like a dream and I bought in full knowledge she would be thirsty, but having always been in this condition, I don't have anything to compare to! In Feb I gave it a full service with new air filter, made sure everything was tight, replaced some cracked vacuum tubes, new tyres and chain/sprockets... Bike has 25k miles and is on original sparks; they look slightly worn but not too dirty and with sharp electrode tips, although this is my first experience of iridiums. FPR isn't leaking. It comes to temp quickly and runs at normal temp (  

Any advice will be greatly appreciated

It does seem awfully low. Even in the depths of winter with shit fuel and stop & go traffic, the absolute worst I see is around 34 MPG US. Usually I'm between 38 and 44 MPG US.

 

This is a bone-stock '02 with 120,000 km.

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I also have a 2007 VFR800.  

 

When I first got mine and it was completely stock, it would get 41 mpg in mixed highway/city/canyon riding.  Mostly highway it got 44 mpg.  

 

After I modified the bike with a Power Commander, that mileage dropped considerably to 36-38 mixed highway/city/canyon riding.  Mostly highway 39-41 mpg depending on how fast I was going.  

 

So it sounds like yours is normal or pretty close to normal.  The only way to get better mileage is to hook up the o2 sensors back on and let the ECM adjust fueling and lean it out closer to 14:1 air/fuel ratio at part throttle/light loads.  I think the PCV has that capability if you add in their o2 sensor and wire (expensive).  With the PCV installed and the 02 sensor deleted/non-functioning, the engine is running around the 12:1 air/fuel ratio just about all the time.  It's nice at WOT or sport riding, but it "wastes" some fuel at part throttle/light loads.  

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With a PCIII my 6th gen gets about 40 mpg (US gal) in typical mixed sporty(ish) riding.  The worst I ever got was 33 - that was going over a twisty high altitude mountain pass just wringing the snot out of it.  So it does seem low.  If you can find a shop with a exhaust gas analyzer you could have them check the air / fuel ratio for you - or maybe install a meter and connect to an O2 sensor in one of the ports and keep an eye on it on the fly.  It sounds like it could be a bit over-fueled. 

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Thanks for responses, all! Interesting re the a:f ratio as I was wondering why economy doesn't improve if I feather it everywhere at <4k. Reassuring that there's probably nothing "wrong" with it though, I will have to meditate on whether I can be bothered to throw another £300 at it for the autotune over just burning a few more dinosaurs 😄

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Welcome to the asylum. We like to see a pic of your machine. To assure us you are not a figment of our imagination.

 

I've no experience on sixth gens so I'll keep quiet on that note.

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🙂I am real as far as I can tell, although I am unable to prove I exist outside of anyone else's head 😉 

 

2007 UK pattern 800 with powerbronze screen & hugger, GPR ``thunder deeptone'' exhaust and quite a lot of the black plastics painted silver very inexpertly by the previous owner. Have half-stripped the bike looking from problems on advice entirely from this forum & the Haynes manual, so hopefully I will contribute something back eventually ^^

20180507_190431.jpg

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Looks pretty sharp.

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I'm sure this has been asked loads, so rather than start a new thread I'm putting it in here. My VFR needs its first fill up in my ownership. Fuel light has just started flashing. how many miles does it have left before I am stranded? Nearest fuel station from work is 6 miles so I expect I'll be ok for that.

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1 hour ago, anth85 said:

I'm sure this has been asked loads, so rather than start a new thread I'm putting it in here. My VFR needs its first fill up in my ownership. Fuel light has just started flashing. how many miles does it have left before I am stranded? Nearest fuel station from work is 6 miles so I expect I'll be ok for that.

 

6 gen Owners Manual states when reserve segment flashes you have approx 3.6 litre or 0.95 US gals.Based on a conservative fuel usage of say 5.5 litre per 100k that would give you 65 kilometers of range OR 40 miles.

Post Edit - Sorry had to change the figures slightly, had my 8 gen fuel economy in mind.!

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5 minutes ago, Grum said:

 

6gen Owners Book states when reserve segment flashes you have approx 3.6 litre or 0.95 US gals.Based on a conservative fuel usage of say 5 litre per 100k that would give me 72 kilometers of range OR 44 miles.

Nice thanks. I thought it would be about half that. 

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To the OP; I wouldn't worry about those figures. For reference I have an '08 with Remus pipes, PC5, PAIR removed and I do pretty much the same sort of mix of riding on my 11 mile daily commute. If I got through the city centre every day I can expect to see low 30s (UK MPG) and in the summer months if I go the long way round the bypass I get around 36-37. On long journeys (which I rarely do to be honest, I prefer the car for motorways) it goes into the 40s. 

 

During winter (I ride right through the year) I've seen it dip to at worst 27mpg.

 

You'll tend to get replies stating awe inspiring MPG figures from our friends in the US and/or Australia where they have much larger, longer roads to make better use of fuel economy. Here in Blighty we have shitty little congested roads that mean the big lardy arsed VFR likes to gulp fuel rather than sip.

 

My ZZR1400 does even worse on the same commute btw, now that gets expensive at fillups...

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Being small and a light weight, I usually get ~50 mpg on my fifths. I find my best mileage comes when I keep revs below 5,000. But when I Having Fun it can drop into the low 40's.

 

One surprising finding. I was reluctant to get a taller touring screen, resulting in more frontal area, yielding lower gas mileage. Once installed it raised my mileage by ~ 10%. I figure it replaced the aerodynamic brick my shoulders present thus increasing mileage above 50 mpg. :wheel:

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