Fastest FJR

[SkooterG]

my data logger shows a max of 162mph at ~8700 RPMs. I don't know what the speedo indicated, but I would estimate about 172mph based on a 6.6% speedo error I calculated at a lower speed one time. It may have possibly gone up another 1 or 2mph with some more time, but probably not. Speed is pretty accurate in the data logger as it is based on a calculation involving the 42 pulses per rotation of the ABS sensor on the rear wheel and the diameter of the tire. That would make 9000 RPMs come out to about 167mph.

Wow. Did the FJR's gearing change that much from Gen I to Gen II? Are you sure about those numbers?

When I hit the gps speed of 160mph my tach was showing about 10,500 rpm. Any time I get over 150mph (gps) the tach is showing over 9,000 rpm.

One thing I have noticed that I don't understand is a non-linear speedo/tach relationship. For instance, lets say my tach at 75mph is 4200 rpm. Then at 150mph, it should show 8400rpm. But it doesn't. The tach will be significantly higher. So the graph may work in theoretical world, but in reality, something - tach, speedo, rear wheel slippage is introducing some error.

 

[Bungie]

One thing I have noticed that I don't understand is a non-linear speedo/tach relationship.

Speedometer error is definitely non-linear. Verifying my by GPS shows it out only about 2km/h at 100kmh, but its out 6km/h at 90km/h. Then its back out another 8km/h at 120.

The 100km/h one kind of threw me for a loop when I'd run 15 over to compensate.

 

[UselessPickles]

my data logger shows a max of 162mph at ~8700 RPMs. I don't know what the speedo indicated, but I would estimate about 172mph based on a 6.6% speedo error I calculated at a lower speed one time. It may have possibly gone up another 1 or 2mph with some more time, but probably not. Speed is pretty accurate in the data logger as it is based on a calculation involving the 42 pulses per rotation of the ABS sensor on the rear wheel and the diameter of the tire. That would make 9000 RPMs come out to about 167mph.

Wow. Did the FJR's gearing change that much from Gen I to Gen II? Are you sure about those numbers?

...

So the graph may work in theoretical world, but in reality, something - tach, speedo, rear wheel slippage is introducing some error.

My guess is that both the speedo and the tach on the bike have error in the digital-to-analog-to-mechanical-motion conversion. The values in my data log are simply calculations from the digital signals. The RPM logging is going to be quite accurate, with the speed logging having the most room for error caused by a difference between the actual circumference of the tire at that speed vs. the calibration value that was entered for the circumference that is used to calculate speed from rotational speed of the tire. I've tested at steady cruising speeds and the data log was always within 1-2 mph of my GPS. The GPS has its own accuracy flaw in that it only reports average speed between updates (~1 second on my Zumo).

-- edit --

And I also have an accuracy flaw in that I cannot maintain a perfectly steady speed for a perfect comparison between GPS and data log speed. All that considered, I think the data log can be considered to be quite accurate.

 

[Bounce]

his buddy with an 08 FJR got 172

the first lier never wins.

 

[blueman]

Do's anyone remember the dude who installed nitro on his FJR. Is the bike still alive.!

 

[ShawnKing]

And I do believe those are the exact words you said to the officer - "but, it really didn't feel like I was going that fast officer!" B)

DAMMIT! I *knew* I was forgetting to pay something...