Spedometer way off!!

So I just purchased my 6th gen 2003 VFR this season and have been taking it on some longer trips (Around 400miles from IL to OH). This is my first real street bike so I have been getting used to the dynamics, such as speed.

On my first 800 mile round trip back home I noticed highway traffic was moving along at an average of 90mph in a 70. I thought nothing of it and thought is was a good day.:biggrin:

After my second trip back to Ohio, I noticed traffic still seemed to flow in the 90+mph range. This gave me a fairly confident assumption that my spedo was off. But by how much?! In the last leg of the journey back to Illinois, it was getting dark and I was approaching a new generation civic. As I passed on the left I noticed the conveniently visible, glowing digital spedo of the fellow Honda. I synchronized speeds and compared! My spedo was reading 7 mph higher than the civics!

Now I know the Honda's spedo could have been off as well so I’m looking for some feedback... I ran a steady-state 6000rpm in 6th gear with OEM gearing on a flat surface. My spedo reading was 92mph.

Can anyone confirm these numbers, or know how to calibrate?

 

Normal. I would say all Japanese (and probably European, but don't know for sure) run 8-10% optimistic. If it says 80 mph, you're probably doing closer to 73-75 mph. It's been like that since forever, although I did have a '71 Bonneville that was dead on.

But since I've been riding, about 48 years, all the Japanese bikes have had optimistic speedometers.

 

My speedo was a little over 10% off, so yours is real close to that. I verified mine thru a GPS unit. I wouldn't use a car, because what is to say that is accurate?

Speedohealer is how I fixed it

 

Problem with a Speedohealer is that any correction to the speedometer induces an equal amount of error in the odometer.

 

Leave the speedo alone and live with the error. If you ride where you need to know the *exact* speed, put a GPS on it. It definitely sounds like the error you've got is in line with the norm.

 

That's about what my '07 was off by. I installed a SpeedoHealer and the problem is now history. Cyborg is right that it then throws off the odometer, but I don't care about that. I want to know exactly how fast I'm going, not approximately. It's less than $100 and sits between the pickup sensor and your display.

 

if the speedo is off.. why would the odometer be correct ? All data/ info comes thru the same circuit....

 

Clublights hit it, the speedohealer corrects odometer error as well as the speedometer. Totally worth the investment, especially if you're looking at reselling. Mine was almost 20% off when I installed it, so a bike with 20k has 2k more miles that it has truly driven.

 

"They all do that, sir."

 

Yeah, but I just don't see having my odo read 10% low, is a real problem. Some might say it is even a good thing.
But like anything it is a choice. I would rather they both be spot on. But given the choice between a accurate speedo and an accurate odometer, I'll go with the accurate speedo.

 

A +1 for Clublights explanation. I have a Speedohealer set for a 6.9% correction and it is right on with the GPS in terms of speed and exact with the odometer checked against the little white mileage signs 1, 2, 3, etc. you sometimes see on the freeway.

John

 

I have a speedohealer on both of my bikes. The 954 has had one for a while. That bike has been -1 on the front sprocket for almost a year. I just changed out the chain and sprockets on my Viffer and it go the -1 treatment on the front as well. Too bad I don't have a master link to go along with it. (fuck me... I used it last year).

The top speed recall feature is nice for when you are hauling the mail and want to see how fast you went. "Hey Mary, we just hit 148. Cool, eh?" <she giggled>

 

Sounds about right, going by my gps vs speedometer the vfr is 7-9km/h high when I get over 130-140km/h range.

 

I just got back from my first run on my 5th gen with -1 on the front and a Speedohealer. It took -12.3% to get the speedo to read 80mph at 80mph. Tested with a GPS.

 

True but the instrument cluster can be set to calculate the sensor data pretty much any way the manufacturer wants, which is exactly what the Speedohealer lets us do. Popular theory is that companies (Car, motorcycle, RV, etc) deliberately set speedos to read high in order to avoid legal issues like a driver and a lawsuit-happy attorney blaming a low speedo (and the company that made it) for a speeding ticket. As for the odometer, the Federal Odometer Act can get one into all kinds of trouble if the Odo's off by much (Honda's been hit with class actions because of odo error tolerances that someone didn't like). Basically, an instrument package like on our VFRs can have significant speedometer errors while having way more accurate odometers. In my case, verified by GPS, radar (don't ask) and timed runs, my '05 has a speedo error of +9.2% and odo error +.7%. With a speedohealer on the job the speedo was spot on but the odo read .9 miles for each mile traveled, again verified by GPS and timed runs...

 

They could easily set the speedo to be optimistic and the odo to be spot on. The speedo has to be either spot on or optimistic by law, but can't be pessimistic (so you aren't going down the road with a reading of 50 only to get a ticket for 55. And so in an accident you couldn't sue because you thought you were going slower than you were. Now there has to be a certain amount of production tolerance in the units, so you want to have it so the at the extreme of the range you are never close to violating the law by being pessimistic.
Plus the manufacturers know we want to feel like we are really fast ;-)

Now if the odo is optimistic 10%, the manufacturer would not be diminishing my value and causing my to get more services than necessary. After all higher mileage means less value. And the quicker I appear to be rolling on the miles, the sooner I have to come in for a service -- they hope.

Yes largely the same data, but manipulated and spit out differently.