The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: LJ. on 15.12. 2011 10:51
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How would you wire up an electronic rev counter to a magneto bike? I'd like to get a rev counter but as the chronometric ones are hard to come by... An electronic one seems a good alternative.
I'm thinking of Primary or secondary windings within the magneto and maybe a wire taken from the points, but I just dont know anything about this. Has anyone been down this route?
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Good morning LJ, Iwent down this route earlier this year BSABILL also expressed an interest ,SRM are producing copy tachos for A65's but haven't got plans for A10's until they are sure of the return on the tooling costs. I found aguy in the Netherlands who can provide a working unit which you have to fit in an old case or I'm told you can buy them from Wassells. He was charging babout £100 in euros and was very helpful ,i'll dig out the link I got and send it to you. It takes it's feed from the mag and just needs a pickup wire close to the mag's body to work. A norton dealer whose name escapes me used to sell another version which took its feed from the end cap(bakelite ) of the mag and thats what I was going to do ,money or lack of it put it on hold for this year for me however as I said I'll get the info to you later,best wishes |BobH
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Thanks Bob will be interested to see the link. A built rev counter is costly and its hard to justify considering the counter is not read all that much. I'm looking for a repro one with an acceptable face to match the original Smiths speedo.
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I'll try and do that today,re the repro look I'm sure there is someone I've seen on e-bay who sells the correct looking smiths speedo and tacho faces for just a couple of pounds, that was where my masterplan was leading but cash will tell unfortunately, regards Bob.
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Good morning LJ, Iwent down this route earlier this year BSABILL also expressed an interest
Yep I'm still in the thinking stage though.
I'm sure there must be some way of turning a strobe into a rev counter, the strobe I have take it's pulse from a spark plug lead and turns it into a pulse of light, just need some gizmo to turn it into a count - it's out there somewhere - I'm thinking somewhere like Maplins might have the answer
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Hi All,
Heres the link to the original supplier of the electronic tacho gizmo, http://www.beckelektronika.nl/
Look at "NIEUWE PRODUCTEN" as its in Dutch
I have not yet gotten round to buying a couple of these gizmos for some projects but have sourced some old speedo bodies and the internal castings that support the face , I am hoping to be able to run the signal wiring through an empty drive cable outer?????
(no usable Chronometric parts will be harmed to produce these *smile* *smile* LOL)
Regards
John O R
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hi i got one from scitzu for my rocket it works ok it has one wire which goes to the ht leads and has a rechargable battery inside a word of warning do not tape tightly to frame as it spoils the signal.
http://www.youtube.com/watch?v=o2hTqNmlcoU
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hi guys, i had a look at this site http://www.beckelektronika.nl/
all in Dutch unfortunately but very good looking stuff. I emailed the owner to see if there was an English version,this is the reply,
Hello BoB,
I'm very sorry my site is not in English.
The reason is:
My English , especially technical, is to bad for a website more over every users manual has to be translated and that's not easy to do when you like to do it perfectly.
Another reason is : there is a lot of work for me here in the Netherlands and Belgium.
At this moment i can't do more.
So i'm very sorry to disappoint you.
Maybe we have someone on the forum who is able to translate, cheers,Bob
Best Regards, Hans Beck.
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Hi kiwi!
Here goes, no liability accepted though, as Dutch is quite different to German. *smile* But I think I got the basic information right:
Speedos:
These speedometers are designed specially for Smiths housings with an inner diameter of 75mm.
The unit is based on the servo-motor principle. So there is no vulnerable moving coil element inside!
The speedo hence is resistant to vibration and temperature variation.
The speedo works from 0 km/h ! and is equipped with a ??? (meerslagen, probably means multi-turn) potentiometer for fine-adjustment.
The input of the speedo receives an analog voltage from the ?generator?, that rises linearly with speed.
Available in 6V and 12V
The included ?generator?, which mounts onto the speedo drive, sends the speed signal via an electric cable, [?] making the fault-prone speedo cable unnecessary. (not totally sure, but I think I got the basic content right).
Note: The speedos are not equipped with odometers!
Rev counters:
These rev counters are designed specially for Smiths housings with an inner diameter of 75mm.
An ?antenna? picks up the required pulses from the HT lead.
Model A (top) and model B (bottom) are the standard dials, it is however possible to fit own dials with a minimum diameter of 70mm.
The needle rotates clockwise on A and B models, but it is also possible to reverse it?s operation (when using a different dial).
Display range can be modified for different dials.
Available for 1-2-3-4-6 or 8cylinder engines, 2 or 4 stroke. Operating voltage 6V or 12V (please state required voltage).
PS: The original illuminating bulb can be retained.
Cheers, Markus
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do not tape tightly to frame as it spoils the signal.
Maybe that's what's spoiling the signal on mine then.
It's Scitsu.
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hi tt the factory told me not to attach the wire tightly to the frame or anywhere also i had to take the resistor out of the wire to improve the signal strengh.try undoing all the the places it is taped to the bike and leave the wire loose except on ht leads then try it .
good luck chris.
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Interesting.
Will do, thanks.
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By George I think that worked!
Thanks.
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Updated!
Right, Well I bought one of those Rev Counter gizmo's from the guy in Holland, Hans Beck, and indeed I found him to be very helpful who insisted it worked correctly before I even paid! http://www.beckelektronika.nl/
The item when purchased is just a dial face with its electronics and three wires, as stated earlier in this thread, you have to provide your own casing. I found it very easy to fit and had the gadget working in no time. The instructions do state that you have to figure out the best place to attach the pick-up and although mine works very smoothly when rolling and bike is under load I'm finding a slight waving of the needle while the engine is ticking over, I'm wondering if this is normal with a magneto and better results would be gained with electronic ignition?
Here are some photos and a You Tube video shot of the the device in action.
http://youtu.be/_5Xp__fiY6g?hd=1 (http://youtu.be/_5Xp__fiY6g?hd=1)
Also in the video while watching the ammeter and battery status monitor, you'll see the performance of my newly fitted DVR2 electronic regulator, another impressive bit of kit. The blue LED indicator is the high beam warning, red is an indicator to show me the brake light and switch is working correctly, and the small switch isolates the battery status monitor LED when bike is not in use. Can't you tell I like gadgets! *lol*
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Hi LJ, good of you to share this info ,it'll spur me on now to get one myself ! the unit appears very smooth I'd expected it to be more eratic ,I know this won't please the purists but looks to be a useful instrument rather than just for show. I only comunicated with Hans by e-mail and even then he was very helpful just a little difficult around the finer points due to his lack of english and my equal lack of any other language. What did he charge you if you don't mind my asking best wishes Bobh.
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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
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If you're still using electro mechanical regulator it's simple to reverse polarity to neg earth.
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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.
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hi guys/wilco, so it it easier/better to change to neg earth? what are the pro`s/con`s of changing over,cheers
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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!
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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
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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.
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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.
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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.
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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
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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.
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Cheers LJ regards Bob