My MPG is too High CTX700

[gregsfc]

That's right; my last three tanks are driving me batty on my Honda CTX700! At or about 79, 81, and now 83; the last two included some miles riding to and from and during a charity ride; some of which the 81 figure was pure tailwind riding north to the event. But the 79 was pretty much just commuting miles; starting with a cold engine twice per day, and this goes up against a bike with a big chunk of riders reporting an average of 67, and another big chunk of riders reporting 69 (sort of statistical modes; not median or mean)--mode is more of what I look at (where are the biggest bars, as this takes out all the ultra urban and aggressive riders from the statistics. History tells me that this bike will crash in mpg during cold weather, I mean way down; not like a typical 6-7 percent loss, but more like a 15% loss, and so once I get this previously-retired vehicle through an entire year, it'll likely fall to a 75-76 average like it did before, but it's still going to be way above most riders.

Yes; I've got an ideal commute; yes I've avoided the common mistakes of most riders who opt for convenience and appearance and therefore, add lots of drag with accessories, as I just strap a milk crate or similar to the pillion seat, which should add near zero drag and could possible reduce drag as an extension of my lower body. The only other modification I've got is a Madstad windscreen, instead of what most riders opt for, which is the Cee Bailey, but from the CTX forum, I cannot confirm that the Madstad actually has an mpg advantage. The only other notable point is that I normally fill up with pure gasoline, but on the E10 tanks I've run through, I've not really noticed much of a fall off in mpg, if any. Yes, I ride pretty conservatively, but I'm not hypermiling. I shift normally around 3000 till I reach third gear, and then I'll upshift at or about 3400, as the bike seems to operate more smoothly that way. Additionally, I am absolutely an anti lugger, and keep my RPM in steady-speed riding in town up to at least 2800.

So what's the deal??? I'd like to think that part of the reason I do so well on the mpg front is the vehicles that I choose to ride or drive are smart choices and would love to think that I'm part of a group that has made a good choice in practical, but efficient vehicles, but my super-high results, compared to others' makes it appear that I'm either exaggerating or modifying or hypermiling. I'm doing none of that, but I'm getting 24 in a gas-powered, full-size pickup rated at 19/26, 22 combined and a mode on here at or about 17 mpg. And for my bike, I'm getting 77 versus a vehicle that's rated by Honda @ 64 and has it's two biggest mode figures at 67 and 69, respectively. I've checked my odometer several times against a couple of GPSs. My bike comes out around 2% over represented consistently, and so I always multiply my mileage result by .978 before entering in fuelly. And my truck comes out 1.8% under represented, consistently and so I'll multiply by trip miles by 1.015 just to be conservative.

But I'm still kicking pretty much everyone else's butt; I don't like it, but it's as accurate as I can report it, and it's conservative, as I try to err on the low side.

Any thoughts or suggestions. I'm a small guy at only 5'8 with a short torso, relative to my height, at least for a guy; I weigh only about 145 pounds. I never idle unnecessarily; don't keep extra weight in the vehicle. Try not to do a lot of short trips and keep my speed on the highways not much above the speed limit, but I'm definitely not a hypermiler.

[R.I.D.E.]

Almost every vehicle I have owned-driven-rode has done great for mileage. My 2015 Mirage is pushing 60 mpg this summer. Your bike was designed with efficiency in mind. I would expect to get about the mileage you're reporting if I rode the bike myself. I'm 6 feet and 195 now with the weight dropping (20 lbs so far) after pedaling my bike close to 600 miles in the last two months.

[Draigflag]

You can never have MPG's that are too high, it's a good thing, aim even higher! You should expect good MPG in this day and age, sometimes conditions, be it light, temperature, traffic or weather are just perfect and you don't even realise what effect this can have on your MPG. Just now I drove 25 miles to do some shopping and got 80 UK MPG, (dropped to 74 by the time I got home) and that's in comparison to your bike big, heavy and has a much larger aero footprint. I made no effort at all, in fact I felt like I was driving quicker than usual.

If you want to learn more, then carefully monitor your economy, sounds like you are already. Experiment with driving patterns etc. Cruising at a lower speed will not always save fuel. When conditions are good, take full advantage.

[gregsfc]

I just wish there were a few who ride what I ride that go where I go with mpg at least in the mid-70s. For some camaraderie, sharing our experience, etc.

Sendler owns a CBR 250R Honda. Has built and mounted a tail on his bike; has done some windshield and final drive changes, but has basically left the fairing alone and is now up to about 115 in his daily commutes, U.S. mpg and recently achieved 144 at a Vetter FE Challenge. I competed in 2014 with my stock bike and a big box on the pillion seat and achieved 101. But I'd like to go where Sendler has gone to get even more mpg. The folks on Ecommoder are too far over my head mechanically speaking. I'm not sure where to start or how to get some help. Would love to have a tail on my 670 cc bike and get a smaller rear sprocket like is on the DCT version of that bike to slightly raise the final drive gearing and shoot for 85 mpg, U.S. for my commutes. And then show up at the mid-Ohio Vetter FE challenge and give it another shot.

[fazerider]

Even allowing for the bike being lightly loaded and ridden gently you do seem to be getting phenomenal mileage.
I'd check the tyres aren't over-inflated and take a look at the spark plugs to make sure it's not running lean… otherwise just enjoy its frugality!

[gregsfc]

Thanks. Yes I've checked new tires, checking the odometer versus GPS, and the Michelin P4s cause a 2.2% optimistic error but my 76 mpg average is post error adjustment. The original tires measured less than 1% optimistic error so I made no adjustment until these new tires.

Winter time on this bike causes more loss than any vehicle I've ever owned, but I'm still over 70 around freezing temps and up to 79 when it gets warm commuting. Summer trips can return 83-84 post error adjustment. Trips in cold weather is at or about 75 but depends on how cold it is. Phenomenal to me that a 670 twin mc can achieve this high level basically stock.

[R.I.D.E.]

Longer stroke, water cooled, tall gearing, some aero improvements from the factory. It's a much different engine from a screaming 14k rpm short stroke mega high performance typical 4 cylinder bike engine of similar displacement.

Feedback fuel injection (added as edit).

My 250 bikes got similar mileage. 500 CC bikes generally around 60 mpg. Your redline is much lower than performance bikes, with good low speed torque.