Speedo Error!!

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Dodge
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Speedo Error!!

Post by Dodge »

Since i've owned my Raptor I've been a bit suspicious as to how accurate the speedo is. On many occasions, I have been going along on the A30 dual carriageway at an indicated 70mph, (the odd time i've been behaving!!), and have what seems to be everyone and his uncle come by!! Now I know these days most people usually do about 75 to 80 on a 70mph road but things were getting silly!!
This weekend I decide to check out how far out my speedo is and what a shock I had!! With 'er indoors sat nav cable tied to the bars off I went. Hmm, as soon as I set off I realised things were not right, an indicated 30mph was a true 27, 40 was about a true 36 and so it went on.
Hitting the A30 I opened her up, bloody 'ell! 70mph is really 63, 80 is 72! bugger, getting a pattern here!
I then found a piece of (ahem) "private road" so I could find out what higher speeds ended up as. 90 is 81, 100 is just over 90 etc etc.
Ok, on bog standard gearing and with standard size near new tyres my speedo is as near as dammit reading 10% fast. This means the day I saw an indicated 142mph, (on that private road I mentioned), I was actually "only" doing about 127 - 128mph! Sorry to piss on your pub bragging stories people, but assuming all Rappies are similar, how crap is that?
One bright thing has come from this though. I was looking on that internet thingy for a speedo healer to put things right, and came across an engineering company just outside Truro that deals in them. Wonder what they do then? A look at their website was very interesting, they specialise in putting Kawasaki ZX1000r and Saab Turbo engines in Smart Cars, and guess what car the missus has got? Do you reckon she'd notice?
Dodge
40 years a biker,..........and still a twat!!!!!!!!!

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Cagiva Raptor 1000, GSXR 7/12 Slingshot Streetfighter, Granada Cosworth
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snapdragon
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Re: Speedo Error!!

Post by snapdragon »

ewww how very odd, The only time mine has been 'checked' was one of those roadside 'you are doing xx mph slow down' type camera/screens and it was exactly what it said on my speedo :nod:
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raptor996
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Re: Speedo Error!!

Post by raptor996 »

I may be wrong but i think the speedo reading is taken off the front sprocket . If the sprocket has been changed either smaller or larger then this will effect the reading, assuming its right with standard gearing.
AZ
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Re: Speedo Error!!

Post by AZ »

I`ve checked mine with sat nav and at 30 is a true 29 and 100 is a true 94 so not too far off.Sounds like something adrift there.On the up side ,not likely to get nicked for speeding :thumbsup: .
NOTE; bikes do not have air brakes,lofting the front wheel will have an effect on a bikes braking efficiency.
dont arf get the adrenalin pumpin tho!!!
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Miz
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Re: Speedo Error!!

Post by Miz »

raptor996 wrote:55 years agoI may be wrong but i think the speedo reading is taken off the front sprocket . If the sprocket has been changed either smaller or larger then this will effect the reading, assuming its right with standard gearing.
That's right, have a look at Gearing Commander


You could have a play with the sprocket sizes and see what matches..
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Dodge
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Re: Speedo Error!!

Post by Dodge »

Hmm, bit odd this!
Just checked my bike again, 16 tooth front sprocket, 40 teeth on the rear, rear tyre 180/55/17 michelin pilot 2ct that has only done about 500 miles so everything is bog standard, but speedo is 10% out!! Any ideas?
At the end of the day i'm not that bothered 'cos a speedo healer will sort things out, just curious to know whats causing the error?

Cheers

Dodge
40 years a biker,..........and still a twat!!!!!!!!!

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Miz
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Re: Speedo Error!!

Post by Miz »

Have you checked that the sensor is fitted correctly into the casing, that the flags are all clean and undamaged?

10% is an allowable error on a speedo, although these days it is unusual.
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Hairy_Mark
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Re: Speedo Error!!

Post by Hairy_Mark »

On the original subject,
I think mine is okay. I never seem to have the curious tailbacks, or people going past on the motorway. Then again, mine normally reads a bit low, I think, so I always account for this imagined phenomenon by speeding up to compensate, whilst constantly checking the mirrors for cuntstables* (typo) who may disagree with my opinion.

Off the subject, the best speedo error I've ever had was when I bought a 2nd hand FZR1000 Exup from a dealer. The speedo didn't work at all. I went out of Carlisle to give my new bike a try, passing through a 30, 40 and 60 limit on the way. I was just trying to adjust the pathetic little mirrors after overtaking a string of metal snails, when I saw a police BMW behind me, some distance back.

Panic set in and I used the rev counter, slowing down to the revs which was sixty on my old CBR600. Confident now that plod wouldn't be able to pull me over, I relaxed. Plod pulled alongside a bit later and gave me the dreaded hand signal to stop.

Somewhat perplexed, I did so at the next junction. He stormed up to me and said, "you went through the 30 limit at 40, the 40 limit at sixty, got to the 60 limit and just fucked off! Then you saw me and slowed down to 75!"

I thought that this didn't sound too good, so gave the excuse about the defective speedo.

Plod says, "I don't give a monkeys about that, You're in for a bollocking!" He paused and I looked suitably ashamed. He added, "Consider yourself suitably bollocked...now, what's the bike like?"

Could it be? I'd been let off with 9 points? I decided to test the water. "I don't really know," I replied, "I've only been on it ten minutes and the police have stopped me!"


To my delight, he laughed. Then he astonished me. We were on a side road to a village called Dalston. His bike was in front of mine. He said, "I've always wanted a shot on an Exup. If you'll let me have a go, you can ride the BM to Dalston."

I'd love to have done it, but the big brute and police gear was too much for my short legs. I reluctantly told him this. He looked sad, too, but told me to follow him for a while. He would hold up his hand at 30, 40, 50, 60 and 70 (despite the fact we were in a sixty limit). I had to look at my revs in top at each speed, so that the 'wankers in the cars' didn't pull me for speeding. He then waved and took off.


*Not all police are bad...that one was a proper biker and a true gentleman.
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The author has recently been declared sane.
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Bear of Little Brain
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Re: Speedo Error!!

Post by Bear of Little Brain »

Dunno if this is how to add photos… First attempt. Let's see if it works:

Here's an accurate calibration:
Attachments
57001_speed.jpg
57001_speed.jpg (22.84 KiB) Viewed 8542 times
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Dodge
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Re: Speedo Error!!

Post by Dodge »

Now that picture is what I call "making progress"!!
Been out on mine again & am giving it the extra 10% on the speedo, that's much more like it! Still gonna get the speedo healer at some time tho'
On a different note, what's the highest indicated speeds you lot out there have ever seen on your Raptors?

Dodge
40 years a biker,..........and still a twat!!!!!!!!!

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Cagiva Raptor 1000, GSXR 7/12 Slingshot Streetfighter, Granada Cosworth
AZ
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Re: Speedo Error!!

Post by AZ »

152 head down `n` bum up holding on for dear life.Too bloody fast for an unfaired bike.
NOTE; bikes do not have air brakes,lofting the front wheel will have an effect on a bikes braking efficiency.
dont arf get the adrenalin pumpin tho!!!
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vassilis67
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Re: Speedo Error!!

Post by vassilis67 »

204 kms that is.
It's all greek to me....
Red Mist
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Re: Speedo Error!!

Post by Red Mist »

Erm, a mere 120 mph. It's faster than I generally want to go. Thought it was fast at the time, but seems from here that it was more like a true 93 mph. :(

I'm sure my speedo is a bit fast, but I don't think by too much. At an indicated 80 on the motorway, I'm usually in the fast lane and overtaking lots of cars.
roadrunner
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Re: Speedo Error!!

Post by roadrunner »

all speedos are incorrect my 650 raptor at 100klm is really doing 94klm knowing this i try adjust my speed with this error in mind.In Austalia it is acceptable for speedos to be out 10% as long as the reading does not indicate a slower speed than you are actually doing. that is why you end up with cars dawdling along thinking they are on the speed limit when they are probably doing 10klm under.the speedo on a mates bandit was 10klm out at 100klm when we tested recently.A gps set up is the best check up as there is no tolerence from plod in Victoria.they think doing 110klh on an open road is speeding a real nanny state.years ago we had no speed limit once out of the towns
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