New member here to learn!

[beatr911]

gregsfc, I agree that Craigs constraints are a little too rigid. Not everyone needs to carry 4 bags, even occasionally. But I do see his point of the bike having more utility. Craig is looking well beyond how we use motorcycles today. The efficiency of the CTX should be compared to the Vetter contenders, Honda has done a good efficiency job here while conforming to the norm of motorcycling styling for todays market.

Yes, streamlining is a key to reduced fuel use at speed. But as fish and birds are not only one shape there must be freedom of design to achieve a balance of emotional engagement to the shape, utility and aerodynamic slickness. Efficient motors and engines play a part but he is addressing only the shape.

One of the problems with Criags design is it getting blown over when parked by very strong wind gusts. It has a lot of side area. There are various ways to address this. The other big one is it's just difficult to mount the shell assembly for most people, so this is just ground work to hopefully influence future design for OEMs.

[beatr911]

By my estimation, and this is only me looking at posts at various forums for the last several years, it seems that at about 70mph the very best stock motorcycles get right around 65 mpg. These are usually 250-500cc bikes with some possible 650's and the Honda 700 twin. With gearing changes the 250 Honda and Kawasaki can do a little better.

The only way I see to significantly better this at that speed is through better aerodynamics as Craig Vetter has demonstrated.

Now, if the riding is less than 70mph-ish speeds then the MPG figure goes up in comparison to the 70mph figure on pretty much all bikes. Significantly more so on smaller than about 400cc or so.

To get better than a calculated 70mpg on the 700 twin at rural highway speeds is pretty remarkable actually considering the power, size and (lack of) aerodynamic slickness. And since this is an all-around number including braking and idling I think it's better yet.

From the NC700 forum... "Putting the DCT rear sprocket on the X would drop the teeth from 43 to 39. At 70MPH, this would reduce engine RPM from 3522 to 3194." Don't know how significantly this will affect mileage but it will help the very low first gear you mention. I'd do it if the chain is still in great shape, if not wait like you indicated.

[bschloop]

Welcome gregsfc. Don't get too dissapointed over Craig's grocery bag rules. they are written much more strict than they are enforced. Craig's wife Carol (who is the official grocery tester) will pretty much pass anything that transports the groceries without damaging them, and is easy to load/unload. even if you have to take some out of the bags.
I look forward to meeting you at the challenge, as I will be there too.

[alvaro84]

Originally Posted by beatr911

From the NC700 forum... "Putting the DCT rear sprocket on the X would drop the teeth from 43 to 39. At 70MPH, this would reduce engine RPM from 3522 to 3194." Don't know how significantly this will affect mileage but it will help the very low first gear you mention. I'd do it if the chain is still in great shape, if not wait like you indicated.

I'd surely surely do it if I had an NC700!
A front sprocket replacement (14->15 teeth) on my girlfriend's Hyosung GV250 improved FE by about the amount of difference between the two setups. I'm still surprised, I wouldn't have thought it would help this much.

[low&slow]

Hi Gregsfc, Welcome! You're doing very well with your Honda CTX700. Raising the gearing will help some but you'll need to do some streamlining for the big gains. I'll look for you at the Vetter Challenge at MidOhio this summer.

[gregsfc]

Thanks to everyone for the feedback and support, and I apologize for my rant. I just needed to vent a little, and I surely have no ears in my social circles with my interests or any expertise with respect to optimizing motorcycle mpg.

I truly understand what Craig is trying to do and illustrate with his events, and the focus being on only what is really "needed" for two and three wheel transportation from a size, horsepower, weight, and displacement standpoint. I think the frustration for me arises mostly from the fact that so little attention is paid to fuel economy in our motorcycle cultures, and if this were not the case, I could go to a different type of event that focuses on different designs and engine efficiencies with all types of two and three wheelers and I could more easily meet the restrictions, but since it appears that only a very small percentage of riders even think a moment about anything to do with fuel economy, the Vetter Challenge is about all there is that I can find, and so I'm happy that he keeps putting them on and letting all comers come and ride. I want to come and ride and meet my personal goal with my mostly-stock bike, but I also am excited about coming to see what all the misers are doing; especially the diesels and electric bikes; those streamlined and even those that are not. It's sort of like all the runners that enter marathon events. More than ninety-nine percent of the contestants don't enter to win. Rather, they want to meet their own goals, and they want to hob-nob with like-minded people, and they want to see the best in action That's where I am in this. I'm just wanting to come and be a part of it, and meet my goals with the machine I've got as an added bonus.

I really appreciate, respect, and am in awe of what streamlining does for bikes and the ingenuity of the folks who take on these endeavors, and can't understand why streamlining hasn't taken over the MC manufacturing industry. However, at this time, that's not what I'm in to doing with respect to owning and riding a bike. I'm a daily commuter on a 500 lb bike that averages 72 mpg, and I want to share that experience. I'm not very mechanically inclined, and I'm not willing to take the time or spend the money that it would take me to get there right now in my life. Also, I've got a new bike with a five-year extended warranty, so I'm not going to be lowering the seat or any major mods that's going to permanently change my bike. This may be something I get in to later, but not for now. What I am in to is maximizing and optimizing on the cheap, my very regularly-looking, useful, mostly stock bike without having to put in much effort or without having to put a lot of money in to the endeavor. Getting the best available, practical, cheap, easy-to-design and install windshield, fairing, chain/sprocket combo to maximize my mostly-stock bike is as far as I'm going to be going with respect to this bike.

I also get excited about simple, cheap solutions that work. For instance, I'm very stoked about my ugly top box, even though I didn't have to do hardly anything mechanically to make it work. For $52 I found a Dewalt tool box that has 55 liters of interior space. I took off my seat and strapped the box to it with lashing straps, remounted the seat, and then tied it down in the back to the rear fender with strong cord. It holds large, bulky items very well, because it's tall and rectangular, and it cost me only $62 total, and since it is mounted close to my back and is narrow (only 14" wide), it does not seem to hurt mpg. I know that my box would be even better if it tapered to a point in the rear, but making the bike useful without noticeably increasing drag is enough to satisfy me right now.

Seems to be a great forum with good, helpful folks and topics are very interesting to me. It's good to be here. Sometimes the discussions get way, way over my head from a technical standpoint, but I can still pick up on the main points of most of the posts, so I'm going to learn alot here.

[bschloop]

+1 for simple and elegant. Toolboxes make great motorcycle luggage, especially if they can be made water tight.

[gregsfc]

Checked my Honda CTX, standard shift, against a GPS yesterday on a 94 mile trip. Going to keep comparing for a while to check the variance of my figures, but it looks like the odometer error, at least on my bike at this level of tire wear on these Bridgestones, is more like 2.5%. So assuming 2% error wasn't too far off the mark and my fuelly numbers aren't too wacked!

Went to the Experienced Motorcycle safety course in Murfreesboro, TN @ Blackman High School. To my surprise, no one laughed at my big, ugly tool box strapped to my seat; at least they didn't laugh out loud in front of me. A few of the guys even complimented me on my creative thinking.

[Superfuelgero]

TTU there in Cookeville offers the classes every once in awhile. Go Purple and Gold! That's where I went to grad school, so I still get the newsletters if you want me to inform you of the next session. I'm not too far off if you need help also, but my bike is not an mpg machine. I've been thinking of putting on a local mpg event, but with my time constraints, it'll not as organized as I would like.

[gregsfc]

Originally Posted by xntrx

TTU there in Cookeville offers the classes every once in awhile. Go Purple and Gold! That's where I went to grad school, so I still get the newsletters if you want me to inform you of the next session. I'm not too far off if you need help also, but my bike is not an mpg machine. I've been thinking of putting on a local mpg event, but with my time constraints, it'll not as organized as I would like.

Yeah. The Golden Eagles's campus would have been a much easier location for me to attend. I live about fourteen miles away; just across the Putnam Co. line in Rickman (Overton County), but the experienced courses are put on only in the Boro and in Music City, so I chose the lesser of the two traffic evils.

Good class and was exactly what I needed, even though I was exhausted after the three hour round trip + the three hours of riding during the course. I've been riding for nearly two years now, and have been simply just kind of commuting back and forth in my uneventful, rural commute and not improving my skills much at all. I'm now much better at turning around at slow speeds in a much smaller radius and can now stop on a dime. I still need more practice swerving to avoid an obstacle, but I now know how to set up my own mock course and what techniques to use to improve my skills for those times when the unexpected happens.