speedometer error

[LERecords]

According to Wikipedia:

"As of 1997, Federal standards in the United States allowed a maximum 5% error on speedometer readings.[13] Aftermarket modifications, such as different tire and wheel sizes or different differential gearing, can cause speedometer inaccuracy."

Thus I would think Yamaha should be required to correct the problem.

i think that only applies to auto's... there has been some threads discussing this over the last few years.. i get your concern with it being 9300 but reading 10,000 if it is from a selling standpoint, but hey, you can always email or call yamaha to see what their take is on it.. and 7% is the overall average.. ive tested mine at slower speeds and it might be 1-3 mph off, higher speeds its a little more like 4-6 mph off.. :thumbup:

 

[04fizzer]

7% is a lot. Instead of 9300 actual miles, my odometer will read 10,000...

Actually I use use GPS with WAAS in my other vehicles and their speedometers are all within 1mph at 60mph(gps). I was surprised that regulations allow a 5% on a new vehicle. Certainly there will be some variation as tires wear, but a new vehicle should easily be within 2 or 3%--the only real sources of error for a new vehicle are the tolerance of the tires diameter, and the amount of tire/road slip which is negligible on dry asphalt.

The speedo is off, but the odometer is much, much closer to actual. Adding a speedohealer will cause the odometer to be off the same as the speedo is now.

 

[Bri]

The speedo is off, but the odometer is much, much closer to actual. Adding a speedohealer will cause the odometer to be off the same as the speedo is now.

Really? So you mean that the correct conversion between transmission output speed and distance is used in the odometer but that this value is then scaled to be wrong on purpose before being converted to speed and sent to the speedometer??

OK... since I'm skeptical I'll check the odometer accuracy with my GPS.

It appears that a majority on this forum don't really care whether their speedo is accurate or not; however, when I drive my car I use my speedometer to "push the limit." In a 55 zone I might drive 62 if I need to get somewhere as quickly as possible. Sure I can make the mental calculation each time I look at the FZ6 speedo but why should I have to? This is a simple calculation on a new bike and there is no reason (that I can see) why Yamaha and others shouldn't be within 2%. Since others are saying that all bikes read high, maybe there is some legal reason for it. Either way, I find it very annoying.

Would anyone be annoyed if they were off by 7-10% in engine power? Minimizing engine to engine variation in output power is MUCH more difficult than the a simple conversion between trans out speed and ground speed...

 

[04fizzer]

Really? So you mean that the correct conversion between transmission output speed and distance is used in the odometer but that this value is then scaled to be wrong on purpose before being converted to speed and sent to the speedometer??

OK... since I'm skeptical I'll check the odometer accuracy with my GPS.

It appears that a majority on this forum don't really care whether their speedo is accurate or not; however, when I drive my car I use my speedometer to "push the limit." In a 55 zone I might drive 62 if I need to get somewhere as quickly as possible. Sure I can make the mental calculation each time I look at the FZ6 speedo but why should I have to? This is a simple calculation on a new bike and there is no reason (that I can see) why Yamaha and others shouldn't be within 2%. Since others are saying that all bikes read high, maybe there is some legal reason for it. Either way, I find it very annoying.

Would anyone be annoyed if they were off by 7-10% in engine power? Minimizing engine to engine variation in output power is MUCH more difficult than the a simple conversion between trans out speed and ground speed...

The odometer and speedometer use the same signal, and a scaling factor is added to the speedometer to induce a % of error.

 

[LERecords]

Would anyone be annoyed if they were off by 7-10% in engine power? Minimizing engine to engine variation in output power is MUCH more difficult than the a simple conversion between trans out speed and ground speed...

most cars are advertised with whatever hp/tq, at the crank.. at the wheels is a whole different story..i guess your right.. most of us dont care.. and if your seriously that concerned when your "pushing the limit" just remember something.. its alot harder if not imposible for a police officer to laser/radar you when on a bike.. besides.. its also alot harder/imposible to catch you on a bike :thumbup:

 

[Bri]

The speedo is off, but the odometer is much, much closer to actual. Adding a speedohealer will cause the odometer to be off the same as the speedo is now.

I stand corrected... You were right about the odometer being more accurate. After riding 100 miles today (as per the odometer) my GPS read 98.1 miles for an error of just under 2%. Yet the speedometer is off by a solid 7%.

Seems like Yamaha may have added a 5% error to the speedometer intentionally which also jives with what my Yamaha dealers tech rep told him, "the speedo should read between 5 and 10% higher than actual..." Of course they didn't know why this is (liability maybe??). I called Yamaha and they told me that they won't do anything unless the speedometer is off by more than 10% (which mine will be when the tire nears its end of life). Incidentally they stated that the tachometer can also be off by 10% and that there is no tolerance spec whatsoever on the odometer.

 

[LERecords]

i wonder if it is due to say parts and the way they are connected.. say.. tire to sprocket to chain to other sprocket and factor in the swing arm.. not that it would be a huge discrepincy, but the bike's swing arm going up and down (minor) when going over bumps and such.. just a thought, but maybe they shoot for an "overall" error...

 

[RJ2112]

i wonder if it is due to say parts and the way they are connected.. say.. tire to sprocket to chain to other sprocket and factor in the swing arm.. not that it would be a huge discrepincy, but the bike's swing arm going up and down (minor) when going over bumps and such.. just a thought, but maybe they shoot for an "overall" error...

The speedo error is intentional, and dates back to when it wasn't. If someone was bench racing, the speedo's inaccuracy 'helped' them. Japan Inc. caught on to that, and has made sure that they don't lose bench races by keeping that error when the systems went electronic. Same deal as the dry weight of a bike.... that used to be an estimate based on the component design and had no basis in actual measured values. (that's starting to change now)

Much like H-D had to program in that potato-potato exhaust note when they went to FI. Separate runners to each cylinder eliminated the cause. The reverse shock waves in the older single carb intake that would cause the intake to end up with a belch of exhaust gases in it, to kill every third or fourth combustion cycle went away...... but nobody wants to buy an HD that doesn't sound like an HD. So they programmed in the stumble to emulate that.

Otherwise, they'd sound just like Hondas.