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They must have factored a deliberate percentage gain into the speedo read out. As you said yourself your odo accuracy seems good. You will affect your odo accuracy though if you change your sprocket sizes as the pick up reads off the transmission.
Given the consistency of reports of 10%ish error, I would tend to agree. However, there also seems to be a consistency to reports that the error is less or non-existent in mph speedos. I find this odd, since they come with a speedo that can give readouts in either. Has anyone compared the two different readouts for accuracy on the same bike?
 

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Given the consistency of reports of 10%ish error, I would tend to agree. However, there also seems to be a consistency to reports that the error is less or non-existent in mph speedos. I find this odd, since they come with a speedo that can give readouts in either. Has anyone compared the two different readouts for accuracy on the same bike?
I've compared the MPH and the KPH readout on my U.S. spec CBR250R, and found that both readouts had the same accuracy. I did the comparison after I had changed from a 14T to a 13T front sprocket, installed a Speedo DRD and programed it to correct the readout for the sprocket size change.

From what I understand, some (or all?) of the CBR's imported to countries with metric speed limits cannot be switched to display MPH. Not sure about Canada... one would think that Canadian spec bikes would be able to be switched to either readout mode, just like the U.S. spec bikes can, as we can easily drive/ride across the border.

Makes me wonder if the 300 was originally designed for a 15t sprocket.
It's also strange that Honda hasnt changed the firmware to correct the error.
Maybe not a priority for a low priced motorcycle.
I believe that manufacturers intentionally calibrate speedometers so as to read slightly higher than the actual vehicle speed for legal/liability reasons. Obviously, a manufacturer wouldn't want to find themselves in a position where they could be held legally liable for speeding violations, let alone liability in traffic crashes were excessive speed was a factor.
 
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I believe that manufacturers intentionally calibrate speedometers so as to read slightly higher than the actual vehicle speed for legal/liability reasons. Obviously, a manufacturer wouldn't want to find themselves in a position where they could be held legally liable for speeding violations, let alone liability in traffic crashes were excessive speed was a factor.
Makes sense except the US bikes dont have an error and the US is probably the most sue happy country on earth.
 

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I believe that manufacturers intentionally calibrate speedometers so as to read slightly higher than the actual vehicle speed for legal/liability reasons.
If legal/liability were the reason then one would expect that the same speedo overstatement would apply equally to MPH readings, given that the US is far more litigious than Canada (and the rest of the world.) Are Honda trying to fool us gullible non-Americans that our bikes are more powerful than they really are? I have seen a lot of posturing/boasting of 100MPH equivalent top speeds, which I don't think is truly possible if measured by GPS/radar (I've certainly tried on occasion).
 

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Given the consistency of reports of 10%ish error, I would tend to agree. However, there also seems to be a consistency to reports that the error is less or non-existent in mph speedos. I find this odd, since they come with a speedo that can give readouts in either. Has anyone compared the two different readouts for accuracy on the same bike?
My bike wasn't switchable between the two modes, some models for certain markets dont have that function. There's a thread somewhere about all this from a couple of years back.

The metric models have the extra 10% built in is so the Bangkok freeway jockeys doing their top speed Youtube clips have good bragging rights. :laugh:
 

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Ha! I posted pre-coffee, which is always a mistake. All I have to do is switch to mph and check it against radar at 62 mph. If there is an error, the math is easy. As for the mph/kph thing, I just assumed that all the 300s had the same speedo function. Global market products tend to be that way, but I can see why some markets (like Canada/US) have more need for the capability to switch.

As for the error, I can honestly say that I have never owned a car or motorcycle where the speedo showed over true speed (assuming no modifications). They have varied between slightly optimistic and downright wishful thinking. Definitely intentional.
 

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Another good day out to Mid-Wales to ride a particular road. Lots of ups & downs and alternating between long straights and twisty sections. Generally riding about 7 -8 mph over the speed limit with the occasional overtake going up to 75 - 80 mph.. 220 miles and my mpg (UK) was 104mpg. I'm very happy with that. On my 650 Deauville it would have been about 58 mpg.
 

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Must clarify last post . in 30 or 40 mph zones I do 33-34 and 45-46mph. But only if conditions are suitable.
 

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Must clarify last post . in 30 or 40 mph zones I do 33-34 and 45-46mph. But only if conditions are suitable.
OK, will modify draft e-mail to North Wales Highway patrol I had written up. ;)
 
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I am still in the break-in period of my bike (at around 400 miles currently) and my gas milage has been 61mpg. Majority of the miles has been freeway/highway riding. What is everyone else getting?
I’m sitting at 84 mpg with a lot of twisties and city driving. Mpg goes down on the highway. CB 300R.
 

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Got 240.8 miles on my last tank. Last bar was flashing for about 10 miles. Mostly highway riding between 55-70 mph. Most readings are between 70-85 mpg.I'm very light and am fairly kind to the throttle.
35016
 
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