Electronic Tacho

redbloke1956

Well Known and Active Forum User
Non-VOC Member
IMG_6623.JPG

Hi all, has anyone fitted the new Electronic Tacho from the VOC Spares ? I am having trouble with initial setup, any help appreciated.

Regards

Kevin
 

redbloke1956

Well Known and Active Forum User
Non-VOC Member
All Good, got it sorted....Rule #1.... DO NOT FOLLOW INSTRUCTIONS
When I followed instructions to the letter (multiple times) outcomes were nothing like mentioned in documentation.
Installation: EASY
Setup/Calibration: IMPOSSIBLE (if you follow instructions)

Kevin
 

A_HRD

Well Known and Active Forum User
VOC Member
All Good, got it sorted....Rule #1.... DO NOT FOLLOW INSTRUCTIONS
When I followed instructions to the letter (multiple times) outcomes were nothing like mentioned in documentation.
Installation: EASY
Setup/Calibration: IMPOSSIBLE (if you follow instructions)

Kevin

Well done for sorting it Kevin! I take it you'll amend the instructions and send them to the VOC Spares Co so that others don't have to experience your frustration?!

Peter B
Bristol, UK.
WANTED: Series 'A' Front Frame
 

BigEd

Well Known and Active Forum User
VOC Member
VOC Forum Moderator
All Good, got it sorted....Rule #1.... DO NOT FOLLOW INSTRUCTIONS
When I followed instructions to the letter (multiple times) outcomes were nothing like mentioned in documentation.
Installation: EASY
Setup/Calibration: IMPOSSIBLE (if you follow instructions)
Kevin
Dear Kevin,
Perhaps you could tell us what your difficulty was with the instructions and share your successful solution. This forum is a good place to share good information.
 

Howard

Well Known and Active Forum User
VOC Member
Assuming this attracts people who understand electronics, maybe someone can explain something for me - anything more than 2 wires on a gadget confuses me.
Ever since my tacho gearbox spit its innards out, I've had the wrong ratio gearbox (bought from ebay). It came to a head at Cadwell last year when the noise meter was reading high due to me using the wrong revs for the test.
While in the garage one winter day I noticed a broken instrument cluster off my daughter's 125 Yamaha (single cylinder 4 stroke), having nothing better to do, I connected it to the Egli (Pazon ignition firing twice per rev) and it worked. Reasoning that the tacho would read double due to the Yam firing once per rev, I set about modifying it to fit. Double the reading was easier to convert mentally than 1.3 x of my existing mechanical one, and it would be registering about 3 at 30 mph, 7 at 70 mph etc, which is handy when my bicycle speedo has no light for night time riding - Keep up, I know it's confusing. After several hours stripping bits out of a Smiths clock and fitting the Yam innards I had a presentable looking, working tacho - quite satisfying for one of my quick projects to actually work.

The thing is, it reads the right revs, not double and I can't work out why. The pickup wire goes to a single double output coil.

Any offers?

H
 

BigEd

Well Known and Active Forum User
VOC Member
VOC Forum Moderator
....... Ever since my tacho gearbox spit its innards out, I've had the wrong ratio gearbox (bought from ebay). It came to a head at Cadwell last year when the noise meter was reading high due to me using the wrong revs for the test.
While in the garage one winter day I noticed a broken instrument cluster off my daughter's 125 Yamaha (single cylinder 4 stroke), having nothing better to do, I connected it to the Egli (Pazon ignition firing twice per rev) and it worked. Reasoning that the tacho would read double due to the Yam firing once per rev, I set about modifying it to fit. Double the reading was easier to convert mentally than 1.3 x of my existing mechanical one, and it would be registering about 3 at 30 mph, 7 at 70 mph etc, which is handy when my bicycle speedo has no light for night time riding - Keep up, I know it's confusing. After several hours stripping bits out of a Smiths clock and fitting the Yam innards I had a presentable looking, working tacho - quite satisfying for one of my quick projects to actually work.
The thing is, it reads the right revs, not double and I can't work out why. The pickup wire goes to a single double output coil.
Any offers?
H
With a single double output coil, I assume one low tension pulse to the coil will give two sparks. Is the tacho circuitry counting low tension pulses rather than sparks?
 

Chris Launders

Well Known and Active Forum User
VOC Member
If the ignition on the yamaha is crank mounted it will fire every revolution the same as your egli, it just won't use the extra spark.
Chris.
 

Howard

Well Known and Active Forum User
VOC Member
With a single double output coil, I assume one low tension pulse to the coil will give two sparks. Is the tacho circuitry counting low tension pulses rather than sparks?
I assume it counts pulses, but you know what they say about "assume".
The coil has one wire from the pickup, and both cylinders fire at TDC(ish) every stroke, which I count as 2 pulses every rev. I assumed the Yam fires every rev (if it fires the more usual power stroke only, I'm even further out!).
Durrrrrr ...................... Just realised - the "distibutor" has 2 magnets rotating at half engine speed, but only one pickup. I'd got it in my head there were 2 pickups as well. So it gets one pulse per rev, but as you say, 2 sparks. :oops:

H

I thought I'd posted this yesterday, but it had't gone. :confused:
 

van drenth

Well Known and Active Forum User
VOC Member
View attachment 2411
Hi all, has anyone fitted the new Electronic Tacho from the VOC Spares ? I am having trouble with initial setup, any help appreciated.

Regards

Kevin
I have fitted one , 5 years ago , made by Dutch electronic specialist, electronic "smiths" rev counter fitted in an original smiths housing and it works perfect from day one.
Only the pick-up wire should be fitted in such a way that only spark from one sparkplug will be counted. Normally there is adjusting possible at the printed circuit board for fine tuning.
I am running digital smart fire 4 plug Pazon.

Regards,
van Drenth JC
 
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