Speedo inaccuracy..

L

Locksim

New member
My speedo reads 38mph at a real-life 31mph - the madness continues throughout the range - in proportion so approx 25% optimistic.

Is there a simple explanation? Like it's from a bike designed with a different ratio drive?

Still, it's exciting to do the 'ton' whilst having a pretty safe licence... :D

Simon
 
I can remember feeling distinctly aggrieved riding the SFC into Abington and slowing to an indicated 40mph for the 40 limit sign.

The sodding dot matrix "your speed is" sign told me I was doing 28 and gave me a big, smiley face. Bastard.

(for avoidance of doubt, that was a Vagueliar speedo on an SFC1000)
 
Most all speedos have a built in error as the drive mechanism is magnetic and are really only accurate at one speed. I think manufacturers shoot for about 10% but production variances produce wider inaccuracies. The 70's Z1 was famous for doing 140 at about 98mph.
 
Last summer on the Jota, I was doing an indicated 100kph in a 100kph speed zone when I passed a police bike going the other way. He immediately did a U-turn and came up beside me with lights flashing and told me to pull over. He said he'd clocked me at 115. So not all speedos overstate the speed. Fortunately he let me off with a warning on that occasion.
 
Dellortoman said:
Last summer on the Jota, I was doing an indicated 100kph in a 100kph speed zone when I passed a police bike going the other way. He immediately did a U-turn and came up beside me with lights flashing and told me to pull over. He said he'd clocked me at 115. So not all speedos overstate the speed. Fortunately he let me off with a warning on that occasion.
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Tasmania, the last state that is not bankrupt !
 
Dellortoman said:
Last summer on the Jota, I was doing an indicated 100kph in a 100kph speed zone when I passed a police bike going the other way. He immediately did a U-turn and came up beside me with lights flashing and told me to pull over. He said he'd clocked me at 115. So not all speedos overstate the speed. Fortunately he let me off with a warning on that occasion.
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Of course you were. Cam, that's what we all say...
 
Hi Locksim, not sure what speedo you have, Smiths or Nippon Denso, both have there faults and both can be repaired. I find over time the damping fluid in the Nippon Denso can cause the gauges to stick and read inaccurate, and the Smiths gauges were just badly built ( worn bushed and not lubed from factory. The good thing is I guess, is your speedo is reading higher so you should never be booked for speeding.
 
It's an ND speedo on a 1200T. I have no idea if it's original.  No sign of sticking and it's inaccurate from the word go, in proportion all the way across the range. I'd say it might be the wrong ratio, perhaps.

Simon
 
Locksim said:
It's an ND speedo on a 1200T. I have no idea if it's original.  No sign of sticking and it's inaccurate from the word go, in proportion all the way across the range. I'd say it might be the wrong ratio, perhaps.

Simon
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Honda maybe?  Almost identical from the outside, totally useless internals for Laverda applications...

Or has the drive gearbox been tampered with?  Don't know of any other marque using a similar speedo drive, but perhaps somebody has stuck some wrong gears in there.  Should be 9/25T.

piet
 
That,s me Ian, slowly changing myself into a Ned Kelly lookalike :LOL:, going to wrap the headers with rags, break out the old open face and WW2 flying goggles and head down to Rundle Street.
 
Terry Dymond said:
That,s me Ian, slowly changing myself into a Ned Kelly lookalike :LOL:, going to wrap the headers with rags, break out the old open face and WW2 flying goggles and head down to Rundle Street.
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Something like this perhaps??? 8) :LOL:
Wonder who that is..................

Onyabike.jpg
 
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