6 MPH

[Gixx1300R]

They say that the official top speed for the Busa is 194.Do you believe that the Busa could someway pick up 6 mph from somewhere to squeeze out another 6 mph.Once I had my Busa to 215 indicated on the speedo which should be about 195 mph but I do feel it had a little more to go.I have personaly seen 5 different Dyno readings on Hayabusas on the same Dyno so all Hayabusas might not be able to run 200 mph.

 

[OB_Dirty Pete]

I'd expect lots of Busa owners could get 195 actual in dead calm wind at sea level in 70 degree air.

The problem is "what is actual"? No one can know that until they've been radared or got a speedo correction device dialled in.

99TLR has suggested, as I remember, that the factory speedo can vary in accuracy up to 15% with 10% or so being the norm. Please correct me here 99TLR!

If you see 215 on your uncorrected speedo and take a 10% correction, you're doing 193.5, which seems right for the bike...a healthy Busa.

Of course, your speedo could could be off either more or less than 10%, so you could be going slightly faster or slower.

 

[Guest]

I believe the stock 'Busa is 6% to 8% fast on the speedo at lower speeds (say under 90mph), rising to 8% to 10% fast near top speed.

A lot depends on the particular brand of rear tyre, and how much it "grows" ie, increases rolling diameter due to the centrifugal forces at higher speeds.

Now of course if you have changed a sprocket, you can add an even greater error, giving about 15% error if you have added two teeth to the rear sprocket.

 

[OB_Jamie]

Gixxer1300R,

I have a friend who has a '98 ZX9R. He told me the other day that his bike has gone over 190mph. He said he buried the 190 speedo and it was still coming. I pointed out that the speedos aren't accurate at high speeds. He went on to say that that was the cable driven units and because his was electric, driven off the gear box it was accurate. Since he lives in NY and I'm in southern Pa I couldn't show him he was wrong but let me say HE WAS. Yes there are tail winds and down hill slopes that add speed but as an old hot rodder once told me "It's cheaper to build a fast speedometer than it is to build a fast car" or bike in this case. I'm not blasting anyone I just wanted to let you know. In the old, old, ram air tests that Sport Rider did they took a ZX9 out and ran it on the top end. They said they had the speedo at 170 something and it was only going 160 or something (its been a while since I read the article I could dig it out if you wanted me to though). I don't think that the manufactures do too much of this on purpose but a small percentage of error is allowed. The problem is at 215 10-15% is 21-32mph. 215 minus 21mph is 194mph. The problem is that not too many people are willing to admit that their speedo is lying to them. There are ZX11 guys who've told me they went 200mph on a pipe alone. While I am a ZX11 guy I still don't believe them. Dynos only help make this crap worse. Sitting on a dyno the operator runs the bike in sixth gear up to red line. Since it's not pushing though the wind it pulls it and shows the owner a big number which he soon touts as his top speed if he had the balls to do it. I can change my gearing to do 300mph on the dyno it doesn't mean I can do it. A dyno operator once spewed that since the drum weighs 400lbs, that the engine could push the a bike weighing 400lbs to whatever speed they saw. Also not true. I'm sure you know why, top speed has less to do with weight than it does with aerodynamics.

IF anyone out there works for a motorcycle magazine, please print the speedometer's reading at top speed and then tell us what the radar gun said. Hopefully those few extra letters and numbers in your article can stop all this confusion.

 

[Guest]

When you did 195 was that on ONE wheel?!


P.S. - Boy do these PAC-10 games run late or what?! 12:10AM Central - still 3rd quarter OR @ AZ!

[This message has been edited by Todd (edited 24 October 1999).]

 

[OB_Turbo]

Well said, Jamie. You say that the manufacturers don't do this on purpose. One question, why do the speedo always seem to error on the HI side ??? Hmm, conspiracy...

 

[OB_Dirty Pete]

What I'd like to know is why speedos have error built into them at all.

The people who make these things are supposed to be manufacturers of precision electronic instruments. Why is inaccuracy of +/- 15% acceptable to the bike manufacturers they supply? And why is ALWAYS plus 5 - 15% in the case of speedos?

Suzuki sure as hell wouldn't allow a +/- 15% on pistons, bearings, light bulb sockets, saddle fit or any other part of the bike for that matter.

I believe Turbo is right. The bike makers feed happy speedos to their customers' egos in the same way that insane asylums feed prozac to their inmates.

The sooner we all wake up to this bullshit and complaint to the bike builders and take matters into our own hands with products like 99TLR's, the sooner the UJM cartel will stop treating us like children.

I'm e-mailing the public relations departments of each UJM maker and asking them why they do it. I will copy the editors of the major bike mags.

End of rant.

[This message has been edited by Dirty Pete (edited 24 October 1999).]

 

[Guest]

About the speedo accuracy, in our workshop here as part of our product development we tested a Suzuki speedo (the stepper motor type used in all late model TLR, GSXR, 'Busa)

On our test bench, we fed a measured, very accurate electronic signal into the speedo, and checked the speed displayed on the dial.

There was good news and bad news, the good news was that the quality of the electronics in the speedo is EXCELLENT. They use an inbuilt microprocessor and stepper motor driven needle, and it is a work of art. You couldn't make a better dial type speedo. Linearity was practically perfect, much better than your eye would be able to tell on the dial. Wonderful piece of hardware, and I should know!

The BAD news is that the whole system is calibrated to read fast. This is absolutely deliberate. The GSXR does it, the TLS, TLR, and 'Busa all between 4% and 6% fast on the stock speedos. We have test information from a number of bikes, and this is an "across the board" error, even across manufacturers.

It seems that a 5% "fudge" is acceptable, and standard. No manufacturer wants to push it to 10% and get slammed. Less than 5% and your new sports bike will show a slower speed than your competitors bike, and no manufacturer wants a sportbike that APPEARS to be slower than the other guy's.

The stock speedos are so accurately built, that two 'Busas with the same rear tyre (and same tyre wear and pressure) will both read the same error.

Now if you change the sprockets too...

 

[OB_Dirty Pete]

Jamie I think you're probably right. All I'd get back is a letter saying "We consider it safer to err on the high side...blah blah."

Nevertheless I resent this kind of subtle manipulation by manufacturers and will hop on the speedo correction bandwagon at the earliest opportunity.

As a pilot, you are taught to "trust your instruments" as a first principle. It irks me that I can't trust a prime instrument like my speedo, and that I haven't even got a reliable correction factor for it that I could use to re-compute readings while riding.

 

[OB_Dirty Pete]

Sorry, double post.

[This message has been edited by Dirty Pete (edited 25 October 1999).]

 

[sherm]

99TLR, have you ever checked the accuracy of the tack? Is it more reliable than the speedo?

 

[Guest]

I had my tach checked the last time I had my ZX11 on the dyno. The tach showed 300 rpm higher than the dyno did. Funny thing was, it was not linier. It was fairly accurate up to 1000, then it just added an extra 300 thorught the rest of its travel to red line. The guy running the dyno told me mine was more accirate than most. He said 10% is the accepted norm.

 

[OB_Dirty Pete]

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[This message has been edited by Dirty Pete (edited 25 October 1999).]

 

[OB_Jamie]

We discussed this on the ZX11 site and figured that they error high because if they read lower than you were traveling you'd be getting tickets and taking turns too fast etc. Think of all the lawasuits. I'm surprises that they even sell bikes as fast as ours. Joe Blow can walk in off the sidewalk and jump on a missle. If he should kill himself or someone else (not likely unless its a passenger) the families could sue. If I built bikes they'd have a top speed limiter whick of course would have a simple wire to snip or ground to deactivate the limiter. Then when the lawyers came knocking I'd say, "whoa he modified it, when I sold it to him it'd only go 65."

 

[Guest]

There is a dispute over tacho accuracy. A respected tuner told me that the late model Suzuki tachs read about 1000rpm fast (at redline) on his dyno, and yes I confirmed he was checking from the ignition pickup (ign coil I think) not from the dyno roller.

It has got me stumped. The tach instrument looks to be the same internals in the gauge as the speedo, but why non-linear? Why read high revs at redline? Is this another marketing thing?

If I get the chance, I plan to put a stock tach on our test bench. When that is done I can post a report/graph here of the tach's accuracy and linearity.