Speedometer accuracy?





Puck

Registered
#1
I have been taking it easy on the bike, following the manufactures recommendations on break-in procedures.  I saw that post and web page about going strait to the dyno for break-in “absolutely nutsâ€￾, there is no way I would do that.

My question is how accurate is the speedometer on the Hayabusa?  For the first 500 miles, I kept the rpm below 5000rpm.  At 5000rpm in sixth gear the speedometer reads 95mph.  Between 500 and 1000 miles you are limited to 8000rpm.  At 8000rpm in sixth gear the speedometer reads 155.  Is this correct, seems a little on the high side?  Compared to my R1, I don't feel like I'm going that fast.

I currently have 825 miles on the bike.

Thanks  
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Narcissus

Hayabusa Immortal
Moderator
Registered
#2
Look at about 10% error on both the speedo and tach. If it shows 200, you are probably going 180. A yellow box will fix most of the error.

On the break-in, unless you have worked on engines and have seen the results first-hand on the rings and pistons and differences in dyno graphs, don't be quick to judge. It is not in the best interests of the manufacturers to optimize your engine's power output after the bike has been built.

From a tuner's and engine builder's standpoint, your break-in period ended 775 miles ago and your seals have seated as much as they are going to seat. But don't take my word for it. Research break-ins yourself by asking local tuners and finding other tuners to compare info. Hearsay is a bad thing when not verified, but so is blindly believing every label and manual warning.
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Andy

Registered
#4
Narcissus is right in what he says, but I have heard the argument about nailing the bike from day 1, something to do with glazing the pistons.
I wouldn't try it myself, but the debate sounded good.

PS:4000 miles, run in correctly,pure stock.
indicated 202 mph (ish)
official 184 mph
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#5
I have read in bike mags that the speedometer runs about 8% fast, so if it reads 200
you are actually doing about 184. The above discussed experiences seem to verify that.
Informal tests on my own Busa get about the same results also.
 
#6
Carry a hanheld GPS with you on the bike.

It is very accurate, less than 1 percent error.

You'll now exactly how far off it is and then if you get a yellow box you can set it to your particular deviance of your speedo.
 

MET

The Watcher
Registered
#7
BusaPrime,

Good idea on the GPS the Garmin e-trex can be found on sale for about $110.00 or less. The e-trex is very accuarate as long has it is kept in the open (never uder the hump) so the unit can get the signal.
 

WWJD

Donating Member
Registered
#10
Anyone know WHY the speedos are off so badly?? If you know the degree of inaccuracy, then it's fixable. I doubt the offage is enough to keep us from speeding so that is not it, and the part about turning and stuff WHO CARES! Fix it. It gives us false trip distances, false MPG readings and everything. Done venting
 
#11
My understanding is that bike and auto manufactures have been confronted by the press about the speedo inaccuracies before. Their attitudes seem to be that this is the way they do it and they intend to keep doing it this way. Why? Because this is the way they do it and they intend to keep doing it this way. Yes, but why? Because this is the way they do it and they intend to keep doing it this way. Etc...
 
#13
I heard the reason the speedo is always 7-10% high is that the manufacturer has to qualify the stock bike on a dyno to get smog readings. They take a bone stock motorcycle and run it under load at 55 mph while sniffing the exhaust for emissions. Once passed, they can't change the configuration at all without re-qualifying. By running the bike at 55 mph indicated using a speedo that is too high, they are actually running at 50 mph. The engine runs slower and puts out less emissions making it easier to pass the test. Sounds like a valid reason but I haven't confirmed it.
 
#14
So Blas32, If I go up 2 teeth on the rear then I can look forward to a 14% innaccuracy? That seems like alot. But I'm glad I heard that before I went up 2 teeth.
I guess I need to invest in a yellow box next.
 
#17
... My question is how accurate is the speedometer on the Hayabusa?  For the first 500 miles, I kept the rpm below 5000rpm.  At 5000rpm in sixth gear the speedometer reads 95mph.  Between 500 and 1000 miles you are limited to 8000rpm.  At 8000rpm in sixth gear the speedometer reads 155.  Is this correct, seems a little on the high side?  Compared to my R1, I don't feel like I'm going that fast. ...
FWIW, other brand speedos show this kind of error as well (my BMW K-RS' was consistently +6%). I use a TrailTech cycle computer -- good to 199mph -- for extra trip meters, avg/max speed, etc. and once you configure it for your tire's circumference it's spot on, +/- a little for tire wear. I also use a GPS for longer hauls, but what the heck...
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Also: Your R1 probably has a similar error. I would imagine the "feel that fast" thing is because the R1's front end generates a good deal more buffetting than the Hayabusa, making for much "dirtier" air at speed on the R1. So, since they're *both* probably lying to you, the 'Busa is probably *faster*
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#19
got a speedohealer v4 on mine with 1 down in the front and there online calculator says it`s -10.8% off..i haven`t checked it against a gps or another car but it now seems a litte slow to me?? i did pass one of those radar/speed box on wheels the police put out around here and it said 34mph and i looked down and was just a hair under 35mph so it might be close?
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#20
Using the local laws stationary digital speed reminder device I've found my speedometer to be off by as much as 12 - 15 mph at 80 mph or so.

It is closer at lower speeds.
 

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