Quote:
Originally Posted by beatr911
Welcome!
Noodling around for taller gears for a CB500x I found that the same sprockets are used for both the 500 and the 700 Hondas. The Automatic trans version 700 has a somewhat taller sprocket combination that can swap over to the manual trans model of both the 500 and 700 bikes. I think it's one tooth larger on the countershaft. These are probably dealer only items at this point but the cost should still be fairly reasonable.
Fewer RPMs will do nothing but help the MPG and make freeways RPMs more tranquil.
Good to see such good numbers on the CTX. Do you have a repeatable number for a steady speed, like say 70 mph?
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Thanks to everyone for the warm welcome!
I've got too many variables and have never really been into what a vehicle can achieve mpg wise at a steady speed, because no one really rides or drives a vehicle that way, even though I do understand the usefulness for comparison purposes. I once achieved 81 mpg on one tank when my bike was new at a pretty consistent 65 mph with stock windshield, but I've never checked my odometer against a gps, and that tank did include a few miles of just riding around. I was using pure gasoline, and it was a brand new chain and sprocket. Nowadays, it's cooler weather, I've not taken any long trips, I've got a taller windshield, and the chain/sprocket has been adjusted a couple of times. I'm averaging about 71.5 (still no trip meter verification), but I do assume a 2% trip meter error and have always included that in my calculations.
I think I'll wait until I've worn out a chain or sprocket and then look at what you've suggested. I'd like only slightly taller gearing, so using the DCT sprockets makes sense. Other than just for better mpg, there would be additional advantages to the stock system on the manual transmission. For one thing, this parallel twin revs so quickly (like for sport-bike riding, which is fatiguing when one is not in the mood for quick shifting or high-revving riding), and the way it is geared makes it nearly impossible to ride it like a cruiser during acceleration. A little taller gearing would make it a more useful bike for easy-going riders, and I would think that 1st and 2nd gear would be more useful for around-town riding for any style of riding, however, I wouldn't want to go too much taller, because @ 60 mph, it turns a relatively-slow 3200-3300 RPM, and I'd like it so that I can still use 5th and 6th gear for most of my riding along winding roads, etc, which is part of my daily commute.
Looking closer into the Vetter Challenge, I'm starting to get put a little put off and have lost some of my excitement about the event. I love what Mr. Vetter does has been doing for many, many years, and the fact that he keeps this event going, and I respect his bias towards bikes being streamlined for future transportation, but looking at the supplemental rules, I'm a little confused as why he has decided that only stream-lined bikes that are streamlined in the same way that he has done it have a chance to compete and win without extreme modification, lots of $$$ having to do with building in room for 4 upright grocery bags, which may require up to 20" of vertical height.
In the supplemental rules he discusses some of the complaints that he has encountered from other riders, and his arguments as to why all bikes must pass the 4-bag test to be certified competitors. I think that (really) neither of his assertions are defensible when it gets down to it. Reason #1--He feels that motorcycles need to be usable, and that for a motorcycle to be a first-choice ride, it needs to carry 4 upright grocery bags. I think this in incorrect for two reasons. First, I don't think that MCs need that much carrying capacity to be usable, because I've got a 55 liter tool box on mine and am using it for just about everything I would ever need except to carry very long items, and if I wanted to carry very long items, a streamlined bike like his streamlined Helix would not work for such utility no more than mine would, and secondly, even if one does buy into his assertion that a motorcycle needs to carry that many groceries, why would it need to stay in an arbitrary container such as grocery bags. I could take my tool box in a store, load it up with about three bags of groceries and mount it on my bike; or I could load up about three grocery bags; take it out to my bike; unload the bags into my box, and when I get to my house, simply carry the box into the house in one trip; easier than carrying 4 bags of groceries.
Mr. Vetter's 2nd assertion is that what would we learn by having vehicles designed differently than his streamlined bike if we had bikes of different shapes that would do better holding the groceries in a different manner? I think we could learn plenty. Fuel economy is not just about low drag and running minimal horsepower, and while I understand that a rounded, tapered front, pointed back with feet forward, seat down, and handle bars back is optimal, that does not mean that riders can't show folks what different technologies can do at improving fuel economy. For instance, Honda has shown a concept bike recently with the new 745 parallel twin with a more aerodynamic fairing. They claim 80 mph. And while I understand that it takes only so much horsepower with a streamline package to accomplish this event, and while I understand that a 745 parallel twin, spark-ignition, multicylinder will never win the event, lots of different type rides should at least be listed with other qualified finishers, so that everyone can look and say, wow, that bike will achieve 80 mpg, but as the rules are stated, just about anything else short of alot of money and ingenuity will always get an asterisk by their name and bike.
Anyway, I've still got a good attitude and will still compete and am glad there is such an event, but I'm not going to try to do the modifications it would take to carry all those groceries in the manner that they must be carried. I want to show what my only slightly-modified, on-the-cheap, usable bike can do to myself and to anyone else that might care, so I guess I'll have to do it without being a qualified competitor.