Smiths Chronoelectric tachometer

Shelby-Right said:
Does anyone know what is required for getting a good signal from a magneto HT lead to provide the signal for a new Smiths Chronoelectric tachometer , I know the likes of a timing light type of pickup, sort of products , or those cheap digital gauges just have little clip
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I hope someone comes along with an answer… coz I don’t think it’s possible, I think they use a low tension signal.

Schitsu tachos are cheap, run on an internal battery that lasts a whole season and more, and get their signal from taping a signal wire to the HT lead. Worth considering if you can’t fix the chrono.
 
Fast Eddie said:
I hope someone comes along with an answer… coz I don’t think it’s possible, I think they use a low tension signal.

Schitsu tachos are cheap, run on an internal battery that lasts a whole season and more, and get their signal from taping a signal wire to the HT lead. Worth considering if you can’t fix the chrono.
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I haven't got a chronometric tach , there is one for sale over here for $ 500-600 with a cable and tach gear box but it's off a norton atlas and the seller said it was 1:1 and the tach was slow to return ! . Those 2:1 gear boxes are a ridiculous price, unless its for a tractor , so that's why I thought the new chronoelectric tach , maybe I might email the manufacturer and see if anything is available to get a signal from the HT lead , getting a bit expensive for my old B33 goldstar 🤣🤣 Cheers .
 
I know it's not HT related, but I was getting occasionally erratic behaviour from my Smiths electronic tacho and the Australian agent said that I was likely getting ignition interference (its connected to the dual coil input).
Seem to have fixed it by using shielded speaker wire - just earthed the shield.
 
I use a couple of Daytona revcounters with Lucas mags. Give Digital speedos in the UK a call & get one of the KOSO adapters which work okay. It tie wraps onto one of the plug leads.
 
This is the reply from Caerbont Instruments.

The gauge needs a 12 volt supply and would also need something like a KOSO RPM filter (also 12 volt) to attach to the HT head of the magneto to trigger the tacho.

We do not stock the filter, but they are available on the internet.

You may be better contacting our Australian dealer Howard Instruments for a more local source.

Regards

Peter Wilkinson
Software Engineer
Direct Phone +44 (0)1639 732243
Caerbont Automotive Instruments Ltd
 
My Daytona tach was erratic until I put a resistor inline to the power (?I think? Or was it the pick-up wire?) due to electrical noise.
 
Only Norton Chronometric I have is 2:1.
Scitzu with internal battery may last a season if not too many races. They also have external feed tachos.
As said all electronic tachos may pick up electrical noise.
 
Shelby-Right said:
This is the reply from Caerbont Instruments.

The gauge needs a 12 volt supply and would also need something like a KOSO RPM filter (also 12 volt) to attach to the HT head of the magneto to trigger the tacho.

We do not stock the filter, but they are available on the internet.

You may be better contacting our Australian dealer Howard Instruments for a more local source.

Regards

Peter Wilkinson
Software Engineer
Direct Phone +44 (0)1639 732243

Caerbont Automotive Instruments Ltd
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All I see is a blank screen. Is that your point? Or am I missing a real reply ?
 
Fast Eddie said:
All I see is a blank screen. Is that your point? Or am I missing a real reply ?
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Hi Eddie, I'm not sure what you mean, ...... I copy and pasted the email , and you've quoted it , and I can read the bit about the filter and the 12v supply and the HT hook up etc , can you really only see a blank reply ?
 
Fast Eddie said:
All I see is a blank screen. Is that your point? Or am I missing a real reply ?
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Smiths Chronoelectric tachometer
 
Fast Eddie said:
Thanks, I can see this one (the other was a blank black page at my end ?!).

So what did you decide on in the end ?
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I would like to get the chronoelectric one day, but they are expensive, but maybe cheaper than the all up price of an old mechanical set up I can find a chronometric tach for reasonable money,but they might need a rebuild to , but getting the 2:1 gearbox they Want stupid money for like, $ 500 ! But most of that has come from goldstar pricing , there are similar gearbox's for tractors for $40-50 but would need to look at ratio and direction , I will keep a look out at swap meets etc . Cheers , glad you mentioned about the reply not readable .
 
Any bike which has a pre-1873 motor is 'historic' and I always try to make mine look the part. I found the tacho from an RG250 Suzuki two-stroke is a dead-ringer for the type used on pre 1960s Italian race bikes. I had seen the Gilera 4 when I was a kid. The rubber anti-vibration mount actually fits the steel loop on the front fairing mount on my Mk3 Seeley frame. Thing which looks non-genuine is a small Suzuki 'S' inside on the face, where I cannot paint it out. The tacho has a gearbox on the back which can reverse it's direction by undoing two screws and turning it over.
It is obviously a Japanese copy which was designed to look right.
I have three of them - they cost $50 at the wreckers. The next model of RG Suzuki had electronic tacho.
I think I had to glue a different ferrule to the outer end of the drive cable, I have them on two bikes.
 
Shelby-Right said:
I would like to get the chronoelectric one day, but they are expensive, but maybe cheaper than the all up price of an old mechanical set up I can find a chronometric tach for reasonable money,but they might need a rebuild to , but getting the 2:1 gearbox they Want stupid money for like, $ 500 ! But most of that has come from goldstar pricing , there are similar gearbox's for tractors for $40-50 but would need to look at ratio and direction , I will keep a look out at swap meets etc . Cheers , glad you mentioned about the reply not readable .
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Like I mentioned before, Scitsu tachos are (comparatively) cheap and easy (tape to the HT lead) and accurate.

They are made with three lugs to rubber mount to a bracket which makes them look very ‘racer’.

But I once cut the lugs off and ‘potted’ one into a clock mount using silicone. Whilst it didn’t look as nice a replica chrono unit, it looked perfectly acceptable, worked well and didn’t cost much.

Haven’t got photos cos I did it in about 1860… or so my kids think.
 
Not sure if it is relevant to you - I had problems with accuracy of my Smiths electronic tacho. Good most of the time but off by 10% occasionally.
Caerbont and Howards were really no help at all. Steve ???(something) from Trispark (Perth) was similarly unhelpful - they just blamed each other.
I ended up buying shielded speaker wire from a local Hi-Fi shop and installed it with the shield connected to earth,
Have had no problems since then.
Cheers
 
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