Speedo reading

[Craigy]

This is my 57 flash speedo , I believe the 1450 is the calibration, S608/11 is listed for a few models. This is the correct rubber grommet mount to suit the divers bell nacelle.
The Speedo configuration you should have is the one on the right, with a small flange on the bezel, and the trip meter reset poking out the bottom, the one on the left suits a face mount or bracket mount.
Thomas

Hi Thomas,

That’s brilliant, thanks

[Craigy]

These original instruments are an absolute nightmare. The number you're looking for is on the dial, below the word CHRONOMETRIC. The usual format starts with  S, then the speedo model number? along with is a number which is the key to the whole ensemble and relates the number of turns of "something" per mile." * Plenty of images on the web. Forum members with accurate speedos will hopefully respond with what's out there. M A  represented "Motor Accessories", hence SMITHS M A.

 Something per mile as urban myths range from the number of turns of the cable, the number of turns of the back wheel or now  more closely the number of £££'s for a good example. Those in the know, know, and this is why a genuine unit costs a lot.

Hi Swarfy,

Having trouble replying to your message. I’ll have a look at the brake tomorrow. Thanks for the info. Cheers

 The drive is from the gearbox, so any change in gearbox speedo drive pinion (unlikely) or final drive ratio (possible) affects the reading. But with another unit to hand a comparison is simple, and will show if the problem lies within your present speedo. It is definitely a job for an expert, warnings already on this thread include the fragility of the original dial printing, and you need guile and skill to get the bezel off without damage, then inside there is more precision chaos. And yes, there are EXPERTS and experts. So don't even consider a backyard fix. Indian versions look the part, but the one you have is probably more accurate......

 Later models (A65) took the drive from the rear wheel and use magnetic type instruments. A whole lot simpler. Japanese bikes used shorter cable, saved costs, speedo drive from front wheel, genius!!

 Swarfy.

 *I'm no authority, just what I've picked up over time. Hope this helps.

[Rex]

Can you not get a gps speedometer for the A10?  It seems an ideal solution given that the speedo changes with chain sprocket sizes, tyre size etc.
John

If accurate speed indicating was the only requirement then a GPS type speedo would be ideal. Trouble is (for me) is that they look awful on an old bike.

[KiwiGF]

Probably worth noting that the smiths number on the dial is not a 100% guarantee of whats actually inside, or for that matter outside.

For example, for a while, until computer printing of dials on a one off basis became possible the speedos restored or recalibrated (to a different spec) in NZ either retained the original (now incorrect) dial, but only if it was good enough to be reused, or they had a new dial fitted with no number, or if that didn’t suit the owner potentially it was fitted with a new dial with a wrong number.

I’m glad I have the two chronos I need for my A10 and B31, but if I didn’t I would get any old chronometric and give that as part payment for a restored one (from a specialist restorer) of the correct spec.

Local situations will vary but parts for some trip reset arrangements were once (possibly still are) in short supply, so it would be best to buy one with the correct trip eg either side or bottom, to use as part payment.

[berger]

how long would it take for a GPS speedo to stop working without a charge for the 12V battery, just a rough time would suffice because the berglar build can't afford to have a smiths speedo refurbed or a budget for a speedo, in other words are these GPS thingy's current sapping??  or are they milliamps

[KiwiGF]

how long would it take for a GPS speedo to stop working without a charge for the 12V battery, just a rough time would suffice because the berglar build can't afford to have a smiths speedo refurbed or a budget for a speedo, in other words are these GPS thingy's current sapping??  or are they milliamps

Cheapest speedo would be a bicycle jobbie, with sensor fixed to a spoke, wire going to display on bars, all powered by mini battery, this set up works well. My B31 has one to supplement the chrono which is inaccurate ODO wise. You need one where the exact wheel diameter or circumference can be programmed into it for accuracy, rather than select from a list of common Bicycle wheel/tyre sizes . BackLit one’s are available if needed for MOT.

Eg https://www.aliexpress.com/item/1005006118613313.html?src=google&src=google&albch=shopping&acnt=494-037-6276&slnk=&plac=&mtctp=&albbt=Google_7_shopping&albagn=888888&isSmbAutoCall=false&needSmbHouyi=false&albcp=19367025750&albag=&trgt=&crea=en1005006118613313&netw=x&device=c&albpg=&albpd=en1005006118613313&gad_source=1&gclid=EAIaIQobChMIjJm965jjgwMVOaRmAh2hvAa_EAQYBSABEgIOUfD_BwE&gclsrc=aw.ds&aff_fcid=602cc439480244b0a2a8ab5a07dd4423-1705452297772-04280-UneMJZVf&aff_fsk=UneMJZVf&aff_platform=aaf&sk=UneMJZVf&aff_trace_key=602cc439480244b0a2a8ab5a07dd4423-1705452297772-04280-UneMJZVf&terminal_id=5a1a50b814a548f998b0a99b9464d94d&afSmartRedirect=y

[limeyrob]

I know its over-kill, and its beyond my technical ability, but there's a guy on youtube who modified the rev counter and speedo on a car in a very neat way. He also posted all the instructions.  He put speed transducers on the drives linked to a pair of arduino computers then he 3 D printed the instrument insides to take an RC mini servo to drive the needle.  When it was done it was accurate and invisible.  I think this kit works on 3.3V and 4.5V so 6V will cover it.  I googled "Arduino tacho" and got a surprising number of hits so this must be a popular solution.
https://www.youtube.com/watch?v=eDLsrjLIHxM&t=16s

[berger]

thanks for the ideas but i am THINKING something like this , do you think these types use much current?

[limeyrob]

Very little, but I would also ask if it can work on 6v.  These are rated for 12 - 24 but the circuitry is probably 3.3v or 5v so there's most likely a circuit inside to drop the volts.  It would be worth connecting one to 6v and seeing if it works.  You can also get solid state DC to DC converters for about £5 that can up 6v to 12v,
Don't forget GPS needs sky so its no use in mountainous areas or tunnels.  I use the GPS on my sat nav in my old Series Land Rover as the speedo is way out but I live near Windsor and when the recent intentional security meeting was being held all our GPS went down in a 5 miles radius.

[Topdad]

How much do they cost ?

[limeyrob]

Seem to be from £50 to £500. I'm not sure what you don't get for £50 or do get for £500 as they all looked rather similar to me.  It would be good to get an empty Chronometric case and see if one could be fitted inside.
OK I know its a tacho, but I didn't know these existed until I was searching today. Digital Smiths Chronometric that will take a signal off an HT lead.
 https://www.digital-speedos.co.uk/gauges-c4/chronometric-c-shape-10k-tachometer-p208/s293?utm_source=google&utm_medium=cpc&utm_term=smiths-digital-chronometric-10k-tachometer-smh0013&utm_campaign=product%2Blisting%2Bads&cid=GBP&glCurrency=GBP&glCountry=GB&gad_source=1&gclid=CjwKCAiAkp6tBhB5EiwANTCx1IplTlQlbSekRraDX26-cg2XbuXmV-1kmcKBb2WOl4soMo7gZcjWQBoCJpkQAvD_BwE
This looks good, optional BSA converter and 6 supply (at a price...)
https://www.digital-speedos.co.uk/gauges-c4/highline-chronometric-120-mph-speedometer-p211/s296?utm_source=google&utm_medium=cpc&utm_term=smiths-chronometric-speedometer-120-mph-highline-series-smh0016&utm_campaign=product%2Blisting%2Bads&cid=GBP&glCurrency=GBP&glCountry=GB&gad_source=1&gclid=CjwKCAiAkp6tBhB5EiwANTCx1KEfaQRomDJMJ3RVwHxXZpPtM-i4KD08Eo9npVnLIC_IHjhhR_EFmhoCk7IQAvD_BwE

[berger]

ok chaps thanks for the replies.  i just wondered if that particular unit took a lot of power if i get one for 45 squid it will be run on a total loss 12v  6ah battery on the bitsa berger build that will be nowhere near an original bike. so if this unit isn't a current guzzler i can have  a front headlight with LED on just so the twts know i am on the road.  also a brake light and both front and rear lights wired to come on together if i get stuck in the dark just like i have wired betsy beezer ,  only front light  or both,  it will be very unlikely if i get caught in the proper dark dark though. then i can maybe find a buyer  for the magnetic rev counter and magnetic speedo i bought when i had lost every sense of what i was doing at that time in my life chucking money at this build. maybe in the distant future it might get a dynamo or other thingy fitted but not yet,  i might yet have to sit outside a pub or night club with a  borrowed K9 and my trilby on the floor in front of me

[chaterlea25]

Hi Berger,
Those electronic speedo's will only consume a few milli amps (very little)

John

[berger]

thanks john i was thinking milliamps but needed some back up cheers, i will go for it and forgo my black&tans , stop buying fuel for the fire for a couple of weeks and burn the tory party

[Triton Thrasher]

Seem to be from £50 to £500. I'm not sure what you don't get for £50 or do get for £500 as they all looked rather similar to me.  It would be good to get an empty Chronometric case and see if one could be fitted inside.
OK I know its a tacho, but I didn't know these existed until I was searching today. Digital Smiths Chronometric that will take a signal off an HT lead.
 https://www.digital-speedos.co.uk/gauges-c4/chronometric-c-shape-10k-tachometer-p208/s293?utm_source=google&utm_medium=cpc&utm_term=smiths-digital-chronometric-10k-tachometer-smh0013&utm_campaign=product%2Blisting%2Bads&cid=GBP&glCurrency=GBP&glCountry=GB&gad_source=1&gclid=CjwKCAiAkp6tBhB5EiwANTCx1IplTlQlbSekRraDX26-cg2XbuXmV-1kmcKBb2WOl4soMo7gZcjWQBoCJpkQAvD_BwE
This looks good, optional BSA converter and 6 supply (at a price...)
https://www.digital-speedos.co.uk/gauges-c4/highline-chronometric-120-mph-speedometer-p211/s296?utm_source=google&utm_medium=cpc&utm_term=smiths-chronometric-speedometer-120-mph-highline-series-smh0016&utm_campaign=product%2Blisting%2Bads&cid=GBP&glCurrency=GBP&glCountry=GB&gad_source=1&gclid=CjwKCAiAkp6tBhB5EiwANTCx1KEfaQRomDJMJ3RVwHxXZpPtM-i4KD08Eo9npVnLIC_IHjhhR_EFmhoCk7IQAvD_BwE

I strongly suspect the £500 ones are the same £50 Chinese instruments rebranded and marked up.