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Discussion Starter #1
CBR 300r - I read a few posts on here about the speedometer being off, especially on the km/h models such as mine. This is really starting to make sense. I was just telling my wife that I've noticed when I'm on my bike it seems like everyone is always on my rear end, and when I drive my truck nobody is ever near me (I drive 10-20 kmh over, everywhere)

So now I'm starting to believe maybe it's because on my bike I'm actually going slower than I think. I don't want to find out the hard way and get pulled over for speeding, if I compensate the loss of speed on my own by going 10 kmh over what my speedo says.

How and where do I get my speedo tested and adjusted? Any help would be greatly appreciated

I was thinking of going on the highway with my wife. Tell her to lock her van in cruise control at 120kmh and I'll ride behind her and maintain her speed and then look at what my speedo reads?
 

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Seany, the speedo on my 250 is off by nine or ten PERCENT! Which means if speed limit is 100, and I want to do 10 to 20 kmh per hour OVER the speed limit (I'm like you in that regard!) my speedometer will need to display 132km/hr!!! Very confusing, and really psyches me out!
b
I have a hand held hiking GPS AND the GPS on my iPhone which I used to compare to the speedometer. Both GPSes were identical in their displayed speed and the bike was 9% lower throughout the entire range. What was even more odd was that the odometer itself seemed to agree with the GPSes. It was just the speed display that was inaccurate. I tested this over about 14kms.

One can argue that even GPSes aren't the most accurate method of measuring speed. There's tolerance issues, angle of the road to the horizon, etc. etc. I believe that one of the best methods of determining an EXTREMELY accurate speed would be to set a couple markers an EXACTLY measure distance apart (the further apart the better - preferable tens of metres) and use a digital video camera with a fairly high frame rate. This would give you very accurate time measurements over a known distance from which you can determine your speed.

It would be a fun experiment, but who, really, is going to go to the effort? I would say a GPS is 'good enough'. Just try to do it on a level run.
 

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I dunno about the "R" but my "F" is pretty spot-on according to the Radar we have on Base. If I'm doing 35mph on the speedometer, that's what's showing on the Radar display...
 

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Yeah the metric models read about 10% fast on the speedo, but the odo is bang on. You can improve the accuracy of the speedo by 7% by fitting a 15 tooth front sprocket...but then the odo will be out by 7%.

Or you can fit a speedo healer. Have added a link to the most popular model.

SpeedoDRD
 

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A $15 bike speedo will be spot on and some are more readable than the one on the bike. Even a 10 year old can install and program. Most will read faster than our bikes will run!!
 

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I went for a ride today, and did some testing/comparisons between the MPH/mile and KPH/km's display mode on my CBR250R... for the record, it has 13/38 final drive gearing, and has been corrected with a Speedo DRD and verified by several traffic radar units to be accurate within 1 MPH.

In order to get consistent, repeatable MPH & KPH numbers, I used RPM in a given gear as the baseline and then recorded the resulting indicated speed in both MPH & KPH modes.


@ RPM - Gear - Indicated Speeds - Calculated Speed (KHP to MPH) or (MPH to KPH)

@ 5500 -- 3rd -- 45 KPH & 28 MPH -- (45 KPH x 0.6213712 = 27.96 MPH) or (28 MPH x 1.609344* = 45.06 KPH)


@ 5500 -- 4th -- 55 KPH & 34 MPH -- (55 KPH x 0.6213712 = 34.17 MPH) or (34 MPH x 1.609344* = 54.71 KPH)


@ 7000 -- 6th -- 95 KPH & 59 MPH -- (95 KPH x 0.6213712 = 59.03 MPH) or ( 59 MPH x 1.609344* = 94.95 KPH)


* Where an asterisk is shown, the conversion figure is exact.




As you can see from the mathematical conversions, the indicated speedometer readout is pretty close in terms of accuracy, whether in the MPH mode or in the KPH mode.

And the odometer readout is also consistent mathematically between the Kilometers and Miles modes.

Hate to rain on anyone's parade, but this idea that the speedo & odo can be off by 8% to 10% in the KPH/km's mode, and be dead-on accurate in the MPH/miles mode is simply not true.
 

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I had just gone by a speed limit sign with the radar attachment and my speedo said 35 but the sign said 37. I have a 15T on the front but I can't remember if it was on the previously time I passed a radar sign and it was dead-on with the speedo. Maybe all radar signs aren't the same
 

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@Jkilla71 Your speedo will be reading a bit slow now if you've fitted the 15T front sprocket.

@MotoMike Not disputing your figures at all but think maybe there is a higher margin of error/safety built into the non-american market models. I could tell by feel (and the traffic banked up behind me!) Before I did my tests that the speedo was reading fast. So I tested it on two different police radar signs and got the same result. 10% out at 100km/h. Then I borrowed a good quality Garmin GPS from work and did the same test. Exact same result.
Other riders from Australia have reported 10% as well. Interestingly my 250R previous to the 300 had same margin of error. That's my findings anyways, I'm not bothered what people take from that.
 

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@Jkilla71 Your speedo will be reading a bit slow now if you've fitted the 15T front sprocket.

@MotoMike Not disputing your figures at all but think maybe there is a higher margin of error/safety built into the non-american market models. I could tell by feel (and the traffic banked up behind me!) Before I did my tests that the speedo was reading fast. So I tested it on two different police radar signs and got the same result. 10% out at 100km/h. Then I borrowed a good quality Garmin GPS from work and did the same test. Exact same result.
Other riders from Australia have reported 10% as well. Interestingly my 250R previous to the 300 had same margin of error. That's my findings anyways, I'm not bothered what people take from that.
My 250R speedo was also originally off by 4% from the factory... chalk it up to mass production, which shouldn't be surprising for a $4000 to $5000 USD bike... If we were talking about a Ducati, a Porsche 911, or even a Honda CBR1000RR, one might rightfully expect something a bit closer to precise instrumentation readouts.

The take away from my comparison is that if your speedo/odo is off by 10% in the KPH/km's mode, it should be off by 10% in the MPH/miles mode as well. Likewise, if it is accurate in MPH/miles mode, it should be accurate as well in the KPH/km's mode. That was the whole point of my test. It also showed that if the odo is accurate, so too is the speedo.

There has been much debate and discussion on the CBR250R site on this topic, with many claiming that all US spec bikes have speedo/odos which are dead-on accurate, while the rest of the world using the metric system have inaccurate speedos. That just doesn't seem plausible.
 

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Discussion Starter #13
i think for me personally....

My cousin is a cop, so i might just get him to radar me next time he has his cruiser. That will be a definate answer as to my speedo callibration. I will let y'all know the result when i do it.
 
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Discussion Starter #14
The bike speedo is driven off a magnet mounted at a convenient spot on the front wheel!!

Really? I'd assume it was all internal electronics. I wonder if this is something that moves or gets dirty and it throws the calibration off.
 

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The take away from my comparison is that if your speedo/odo is off by 10% in the KPH/km's mode, it should be off by 10% in the MPH/miles mode as well. Likewise, if it is accurate in MPH/miles mode, it should be accurate as well in the KPH/km's mode. That was the whole point of my test. It also showed that if the odo is accurate, so too is the speedo.
OK so I just went out to do a ride comparison switching from MPH to Km/h like you did Mike.
Before starting the bike I tried to change it over to MPH by using the method I had heard mentioned in threads on the 250R site ie. holding the MODE button down until it starts flashing then push to change etc etc...
Well I **** near pushed that button to the center of the earth with no result :laugh:

Eventually I dug out the owners manual (always a last resort for most males!),found the right page with a note saying 'ED & III ED type only'
So to the front of the book I go to the legend and find that only the European, South African and Singapore metric models have this facility for swapping between Kph and Mph and the Australian, New Zealand and Korean models dont. Hmm....

So.... I'm wondering now if these models of ours also have a higher level of error built in to the speedo units for some reason, but I cant think what the reason would be?!

It did intrigue me that the ODO on both of my brand new CBR's was bang on whilst the speedo was out. :confused:
 

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Really? I'd assume it was all internal electronics. I wonder if this is something that moves or gets dirty and it throws the calibration off.
Yeah, jcctx was talking about some cheap bicycle speedo, not the speedometer on the CBR.
 

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OK so I just went out to do a ride comparison switching from MPH to Km/h like you did Mike.
Before starting the bike I tried to change it over to MPH by using the method I had heard mentioned in threads on the 250R site ie. holding the MODE button down until it starts flashing then push to change etc etc...
Well I **** near pushed that button to the center of the earth with no result
:laugh:

Eventually I dug out the owners manual (always a last resort for most males!),found the right page with a note saying 'ED & III ED type only'
So to the front of the book I go to the legend and find that only the European, South African and Singapore metric models have this facility for swapping between Kph and Mph and the Australian, New Zealand and Korean models dont. Hmm....

So.... I'm wondering now if these models of ours also have a higher level of error built in to the speedo units for some reason, but I cant think what the reason would be?!

It did intrigue me that the ODO on both of my brand new CBR's was bang on whilst the speedo was out. :confused:
My US/English language 2012 CBR250R Owner's Manual had a typo error regarding the procedure: After pushing and holding the Mode button down until the display starts flashing, the O/M says to push the Mode button again to select either km/h or MPH mode… this is wrong, you actually need to push the Reset button to select km/h or MPH. Then you press and hold the Mode button to lock in the display you've selected.


As far as I know all CBR250R/RA models can be switched between km/h and MPH readouts… sounds like they did away with that feature for the CBR300R/RA, at least in certain markets.
 

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Discussion Starter #19
I haven't got my cousin to radar my speed yet BUT I can confirm that my bike (and it's Canadian, and set standard in KM) does in fact switch to miles. I was tinkering with the display today and figured out how to switch between KM and M.... just to settle the debate of our Canadian CBR's not having the M option lol
 

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I haven't got my cousin to radar my speed yet BUT I can confirm that my bike (and it's Canadian, and set standard in KM) does in fact switch to miles. I was tinkering with the display today and figured out how to switch between KM and M.... just to settle the debate of our Canadian CBR's not having the M option lol
Didn't know there was a debate going on whether or not Canadian CBR's had speedos that can be switched. :laugh:

Seriously though, I'd imagine that in those parts of the world where one can actually ride across a border in which one country uses miles and the other country uses kilometers, it only makes sense that bikes imported to those counties will have switchable instrument clusters. UK - EU countries, and US - Canada are the countries that I know of where it would be convenient to be able to switch modes when you ride across the border.

Where as people in countries like New Zealand (like kiwi rider), or Australia, or Asia countries simply don't have the possibility of riding their bikes across a border where miles & MPH are the standard measurement, so bikes being imported to NZ, AU, and those in Asia would never have a need for a MPH/miles speedo.

So SeanyMagic, did you compare the readout in the km/h mode to the MPH mode to see if they correspond to each other?
 
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