Speedo reading fast

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Harry Mirage

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North Lincs
Hi all I’m new to this group, I have a 1200 Mirage 1978 problem with nd speedo reading 10-15mph to fast does anyone as any suggestions. Both speedo and tachometer are new and on the bike when I purchased, the speedo drive has 25/9 which I think is correct.
 
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2 of us were following a cop car on the notorious for being booked Old Pacific Hwy. The bloke in front was doing 40kph and I couldn't understand why as my phone on the dash doing GPS was saying 40kph in the 60zone so I passed and upped it to 55. Later he was asking why I was speeding up that cop's arse. Laverda speedos and GPSs don't match at all. I now understand all those I was doing 200 stories.
 
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Legs said:
One of the advantages of fitting one of those pushy thingos is, dependant on model, it'll give you the time, an odometer, a trip meter, average speed and highest speed attained (which could lead to trouble if checked by the plod). Even had one that gave the temperature.
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That's not really a problem.

Police (at least the cops in Australia) either need your permission or a search warrant to check electronic devices, so I presume that includes electronic speedos. They also need a search warrant to search your vehicle, unless they have good reason to suspect that your vehicle may be relevant to a criminal investigation or is somehow endangering the public.

So if they ask to look at the history recorded in your speedo, just say no. If they check without your permission, any evidence they find is not admissible in court.

But if you don't want to appear uncooperative, let them check the speedo's history. As long as the highest recorded speed isn't time-stamped, just tell them the max speed of 214kph was achieved when you did a track day.
 
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As for speedo accuracy, they can be re-calibrated. Obviously that would involve taking it apart so you might want to take it to an instrument specialist.

If you want to tackle it yourself, it helps to understand how a speedo or tacho works. I'm talking about old magnetic speedos, not new-fangled electronic instruments or Smiths chronometric.

Basically it's a spinning magnet placed next to an aluminium disk on a shaft that has the speedo needle attached at the other end of the shaft. As the magnet spins, it tries to drag the aluminium disk (and the speedo needle) with it. You don't really need to know how it does that, just accept that it does (it's all about induced eddy currents in the aluminium creating an opposing magnetic field).
The faster the magnet spins, the more it tries to rotate the aluminium disk, so the torque applied to the disk is proportional to the speed of rotation of the magnet.
The rotation of the disk is opposed by a spring. The higher the torque applied, the more the disk will deflect from its rest position.

If a speedo reads high, the aluminium disk is turning too far, which means the opposing spring rate is too light, so you need to make it stiffer. Shortening a spring increases its spring rate, so that's what you need to do. Unfasten the end of the coil spring where it's anchored to the chassis of the speedo, pull a bit of spring length through and re-fasten it. You will have to re-zero the speedo needle, but that's all there is to it.

This bloke gives a pretty good explanation.

 
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Police (at least the cops in Australia) either need your permission or a search warrant to check electronic devices, so I presume that includes electronic speedos.
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Not sure about that, at least in SA.
Been to many a motorcycle accident as a member of the emergency services and the cops are always interested in any non-standard electronic device fitted to the bike, they confiscate cameras as evidence, can't see them stopping there though.
Of course it may be different if pulled over for a rego/speeding/mono/burnout or any other naughtyness.:rolleyes: But wouldn't risk it, always hit the 'reset' button.
 
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They're looking for data on phone use at the time of the accident, and guess how often they find exactly that. The cops in Queensland have just opened a dedicated portal so you can send them your Dash Cam footage of Motobikes passing you on Double Lines or any other vigilantly footage you dem fine worthy. If you make this easy they will reel you in on your own data. It would be great to get solid Legal Oz related advice on what the cops can and cannot do with your dashcam or phone or GPS data as evidence. I did see exactly what Cam said about politely refusing permission re a search on a USA site, if they get on the video you say sure search away then you destroy any defence as to what is found from that search.
 
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Vince said:
They're looking for data on phone use at the time of the accident, and guess how often they find exactly that. The cops in Queensland have just opened a dedicated portal so you can send them your Dash Cam footage of Motobikes passing you on Double Lines or any other vigilantly footage you dem fine worthy. If you make this easy they will reel you in on your own data. It would be great to get solid Legal Oz related advice on what the cops can and cannot do with your dashcam or phone or GPS data as evidence. I did see exactly what Cam said about politely refusing permission re a search on a USA site, if they get on the video you say sure search away then you destroy any defence as to what is found from that search.
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A bloke I know suggested that if you were to copyright your name, as soon as they wrote your name on a ticket, you could personally sue them for breaching copyright.
 
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Harry Mirage said:
Hi all I’m new to this group, I have a 1200 Mirage 1978 problem with nd speedo reading 10-15mph to fast does anyone as any suggestions. Both speedo and tachometer are new and on the bike when I purchased, the speedo drive has 25/9 which I think is correct.
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At what speed is it 10-15mph fast? Does the needle return to zero quickly or is it sluggish- I have seen the needle fitted on the spline without enough negative angle ( the needle is actually loaded against the zero stop) and the speedo read 10/15mph almost immediately . If it’s 10mph on the motorway I wouldn’t worry about it. Jason
 
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Legs said:
Not sure about that, at least in SA.
Been to many a motorcycle accident as a member of the emergency services and the cops are always interested in any non-standard electronic device fitted to the bike, they confiscate cameras as evidence, can't see them stopping there though.
Of course it may be different if pulled over for a rego/speeding/mono/burnout or any other naughtyness.:rolleyes: But wouldn't risk it, always hit the 'reset' button.
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I guess they have greater freedom of investigation when dealing with an crash. They can probably impound the entire vehicle and dismantle it if they want to, especially in the case of a fatality.
 
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