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Discussion Starter · #1 ·
The CTX leans pretty good on the side stand and the filler neck has bars going across the opening. The manual shows a side view of the neck but I think I am using a lower fill point but at least I can be consistent between fill ups. That said I used 2.198 gallons to go 146.6 miles. I estimate that to be 66.70 miles per gallon. If you do the math, there should have been about a gallon left in the tank or enough gas to go roughly another 50 miles easily.

Breaking it in, I tend to not hold the speed too steady. It is better to work the engine up and down the rpm range and not over rev or lug it. The break in period is 300 miles
 
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Memory is fickle, but I seem to recall a problem with another new Honda model. Early 70's saw the introduction of the CX500 which had several revolutionary features. Some were seizing, but only those that owners claimed had been broken-in with care. Honda resolved the problem by increasing the bore by 2 microns, probably the only company around at the time capable of working to such a fine tolerance. 25 microns to the thou, and the human hair is 4 to 7 thou, so we're talking REAL small. Anyway, my point is, I'll be talking to a trusted mechanic familiar with the CX500 to confirm or deny my failing memory.
 

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Thanks for the mpg report and other info Bill.

Any thoughts or guesses as to whether or not the odometer is accurate?

I asked this same question on the NCX forum and many members thought I was splitting hairs and didn't appreciate me bringing it up, but honestly, this can be quite a significant error in some vehicles. In my VW Jetta TDI cage, for instance, the trip meter error is between 3 and 5 percent depending on tire brand and tire wear. Due to this gross error in my cage, I include it in my mpg calculations. On the other hand, I've found that my BV350 scooter odo error is less than 1% with new tires, so I don't bother including it in the calculation.
 

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Discussion Starter · #4 ·
to be exact, you could mathematically computer speed at any give rpm but you would have to measure the diameter of the rear tire (160/60ZR17 Metzler) and know the engine to clutch gear ratio (primary on ctx700n is 1.731) and final drive ratio (2.687 16 tooth in front 43 rear and 39 on the DCT models). By mileage markers and radar trailer displays, I think when it reads 40 you are going 39 miles per hour so that is 2.5% off which I think is pretty close. My Hawk was 10 miles slower than indicated at 75 due to different tire size. My VFR was like the CTX. Tire ware does make the diameter change. 1 inch less in diameter changes the formula.
 

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I was asking about the odometer/trip meter. Not the speedo. Are you saying if there is an error in the speedo, it is also in the odo? Others on other forums have said not, but I'm not a physics, engineering, or mathematical thinking guy, so I don't know. In my BV scoot, the speedo is off my seven percent or so but the odo/trip is pretty close, or so says the GPS.
 

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Discussion Starter · #6 ·
The error between mileage posts is off by 1/2 tenth in 2 miles as indicated by the odometer not the speedometer. Since it is digital I would hope they made the with the same error built in but who knows.

I do know iIf you measure the rear tire and calculate how fast 4000 rpms is in 4th gear you should see how accurate the speedometer part of the guage is. I have not done that yet. I may some day. I did that on my Hawk. I went for a ride today and with 280 miles on it I wanted to see what 6000 rpms in 4th was. Looks to be 79 to 80.
 

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The error between mileage posts is off by 1/2 tenth in 2 miles as indicated by the odometer not the speedometer. Since it is digital I would hope they made the with the same error built in but who knows.
Okay. So roughly 2 1/2 percent by the measurement you took... Right?
 

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My 2007 Honda Shadow VT750C2 read 10% too fast. So did my 2008 and 2009 Suzuki Burgman 400's. My 2010 Honda SH150i and my 2012 Honda Rebel were spot on, regarding the speedometer. I've never double-checked the odometer. I'll have to strap the GPS onto my CTX700N, and see what that turns up.
 
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