Fitting an Electronic Rev Counter?

[kiwipom]

hi guys/LJ, after reading your glowing report on these units i decided to order one for my bike. This is the reply that i got from Hans can you explain what the problems where?

 Indeed, recently i sold a rev.counter in the UK.
I made this one for positive earth and i'm affraid to tell you it did not work properly instantly.
The customer had to find out what the best wiring was for a stable reading.
After these difficulties i decided not to make this counters for positive earth.
If you have negative earth, no problem, i will have some more questions for you.
Please let me know.

Regards, Hans Beck.

Hans obviously had problems with positive earth units so what bikes run neg earth? it rules out A10s for future fitting of these units, cheers, Bob

[wilko]

If you're still  using electro mechanical regulator it's simple to reverse polarity to neg earth.

[LJ.]

Indeed it seems that Hans is not happy with the rev counter for positive earth and he could well have been referring to mine. Although I've paid up and am happy with it, he wants me to investigate further as to why it is not functioning as he says it should, can't be fairer that that I suppose.

I will look closer at the signal wire that has been zip tied to the frame, earlier replies to the thread suggests NOT tying too tightly. Earlier problems I had with the device was due to connecting the supply close to the electronic regulator, I then gave the Rev Counter its own voltage supply via a small 9 volt battery and this made a difference.

[kiwipom]

hi guys/wilco, so it it easier/better to change to neg earth? what are the pro`s/con`s of changing over,cheers

[LJ.]

Hmmmm I don't think I'd want to risk changing polarity with this expensive bit of kit without first asking Hans if its okay to do so.

TopDad... Cost was £79.83 + £12.01 post & packing. £91.84. Not cheap but a darn sight cheaper than a recent Chrono on ebay that fetched £400!

[kiwipom]

hi guys/Lj, i think wilco was refering to changing polarity of the bike to accommodate the negative tacho unit instead of the positive one,cheers, Bob
   

[kiwipom]

hi guys, more info from Hans Beck after he watched the utube video,cheers, Bob

I saw the youtube video and i was not impressed.
It must perform better. (we are working on this part).
No problem to make a positive earth counter but with negative earth i know for sure there are no problems.
The counter works with pulses coming from the HT cable or you can connect the signal wire via a resistor to the "hot" connection of the primary side of the coil HT.
So it works with a magneto but also with breakerpoints or electronic ignition.
You know you need an empty chronometric Smith compartment (3 ") by yourself?
On my website (choose speedometer/tachometer) you can see two plates model "A" or "B" which one do you like to have.
The price is euro 95 P & P 2.30 euro
 
Regards, Hans Beck.

[bsa-bill]

Hi guys, I've been following this thread, seems like a good idea so I think I'm in for one when Hans gets it sorted.
on the polarity issue, am I right in thinking the three wires are signal, positive feed and earth, in which case if the instrument was insulated from the frame (rubber mounts alla A65) could the feed and earth not just be reversed, bear in mind folks my electronics Know how has not progressed much beyond the crystal set era.

[LJ.]

I'm thinking that the signal wire maybe too close to the main wires running along under the tank along the frame. I'll try and divert the signal wire well away from other wires and see what happens. I've been doing alot of jobs on the B33 this last week in readiness for the Welsh Dragon Rally next week but I think I might just spare a day sorting this out on the A10.

[a101960]

I'm thinking that the signal wire maybe too close to the main wires running along under the tank along the frame

You could always try shielding the signal cable. Get some coax cable and strip off the braiding and then feed the signal cable through the braiding. The main wiring harness is in electrical terms going to be very dirty and it will give off a lot of spurious electrical noise (especially from the charging circuit). Try also fitting a soft iron filter ring to the rev counter power cable. Bare in mind that the dynamo in particular will generate a certain amount of sparking which in electrical terms causes it to be a radio spark transmitter. Is it still possible to by dynamo radio supressors? Remember them? I am sure that a suitable suppressor could be sourced from somewhere.

John

[kiwipom]

hi guys, more info from Hans Back, cheers,Bob
To convert the polarity of my rev.counter you only have to change one wire on the screw connector (and of course the right power wires to the right battery terminals)
If you have a Boyer ignition with one terminal of one of the HT coils grounded (with pos. earth) you will have a positive going pulse on the output of the Boyer box.
This pulse is perfect (and equal to neg. earth) for my counter.
If you have a normal breaker point ignition with pos. ground the pulse goes negative. In this case i have to adapt the software.
With most of the electronic ignitions there is a spark every revolution. I will have to know this for sure because the counter is adjusted on this information.

[Topdad]

Cheers LJ regards Bob