Tacho adjustment

[Gibbotvr]

On my Z1000J I have fitted a Boyer Bransdon ignition system and now my rev counter is reading double.
I checked with Boyer and they said this is due to firing the coils twice.

Question: is there any way to correct this externally or do I need to send the tacho off to be re-calibrated. Boyer will do it for about £55.

[Al]

If this is the large round J style tacho, they cant be taken ('could be' but its a days work to pull apart and put back together) apart and internally they are mostly electronic. Short of wiring an external electronic 'healer' onto the back, i cant see how it can be done but would be very interested to hear if it can.

The tacho should get one signal from one coil. Number 1 & 4 coil. It is a single black wire; teed into the feed for the original IC igniter. I am not familiar with the wiring connections for the Boyer but if it happens that the tacho is now receiving a signal from both coils it will read double. I cant see that it makes any difference that it is a twin fire coil because both ports fire instaneously but i stand to be corrected. The wire that feeds the coil for 2 & 3 has a dark green wire where the signal coil has black. This green wire should not be connected to the tacho.
Dyna 'S' is a little different perhaps and the power for 'S' is taken from one solitary Red wire that feeds both coils!!!!!
There is no need to make corrections for Dyna 'S' or Dyna 2000. You plug them in according to the instructions and they work correctly for the tacho.
AL

[Gibbotvr]

The black wire is the one I traced from the block that did go to the ignitor. That is the wire that I have connected to the black connector on coil 1 qnd 4.
Boyer seemed to know the issue and can rectify.
Thats why I was wondering if there was an external fix.
There is a module on ebay item number 251613298118
It says for moving coil tacho's, not sure if the J has this type or not.

[z1bman]

what is the kit no of the boyer ?

[z1bman]

what have you done since your other post about your running problems as you say the tacho is reading correctly now ?

[Gibbotvr]

The Boyer kit was 00088

I thought the tacho was but as I now have it MOT'd and on the road you notice with the higher the revs the more inaccurate it is.
At low level revs tick over etc its not so noticable as 750rpm = 1500rpm but at 4000rpm its on 8000rpm.

[Al]

It wasnt very helpful for me to go banging on about Dyna systems but trying to make the point that something could be amiss with the wiring.
When you said 'External Fix' i thought you meant some kind of adjuster on the tacho itself. 'Re-calibrated' i took to mean some internal meddling with the printed circuit board, therefore comment about dissmantling.
If Boyer can fix you up for £55 i would say that was a really good option and i'd let them do it.
Yes, i am 99.9% certain that they are moving coil tacho's. I did have one in bits and i'm sure that was what it was. (So many bits )
Well done getting it MOT'd
PM sent

AL

[Gibbotvr]

Thanks for the input, TBH it might be an electrical gremlin as I am having a few random issues:
Fuel gauge and sender works and then stops.
Speedo not working.
Sidelamp bulb stopped working and now is.
And of course Tacho.
So hey ho keeps me out of the wife's way

I need to get my meter out but its still putting a smile on my face albeit I'm not going too far from home at the mo.

[Coose]

I think I may have the answer, which is as I suspected.

The standard ignition uses two individually-wired ignition pickups, where when each pickup is triggered the IC unit then triggers the appropriate ignition coil.
Looking at the Boyer wiring diagram there are two pickup coils but they're wired in series, with just two cores running up to the Boyer ignition module. This therefore means that both ignition coils fire at the same time, which means each coil and thus the tacho will see twice as many pulses.

It also means that any lead can go on any plug!

As Al says, send your tacho to Boyer if they say that they can mod it for £55.

The manual is here: -

http://www.boyerbransden.com/pdf/KIT8788101.pdf

[rickm]

So it's a triple wasted spark as opposed to the single wasted spark standard system ??

[Gibbotvr]

You can't have too many

[Coose]

So it's a triple wasted spark as opposed to the single wasted spark standard system ??

It looks to be as there's no way for the ignition module to know which pickup coil has triggered the spark.

[rickm]

The Boyer system on the Kawa triples fires each plug 3 times every revolution of the crankshaft, meaning that you need a good fully charged battery for it to work properly. Maybe not such an issue on a Z but you've still got 4 plugs firing twice on every revolution.

[Gibbotvr]

The battery is brand new, but I haven't checked the charging rate yet. No issues in that dept so far though.