Topic: PowerArc with Motogadget Motoscope problem

[h.lanooy]

Hi there,

I'm building a CafeRacer from a CB650 (1981).
The build is pretty far. I have a lot of Motogadget stuff like mUnit, mLock an Motoscope Pro.
All working fine.

I just recently replaced the stock ignition with a Power Arc Ignition system. The Power Arc works with optics timing, more accurate than Hall effect (magnets).
It also delivers 3 sparks per compression stroke. Cleaner fuel burn.
The ignition module has a dedicated tach trigger wire. This wire will give 1 signal per rotation (if you draw the signal from the coil you'll get 3 signals because of the 3 sparks).

If I hook this trigger wire to the Motoscope, the Motoscope won't react or process it. Tach does nothing.
If I hook up a induction signal pick up, this works, but still registers 3 signals instead of one.
If I hook up the green trigger wire form the ignition to another tach (ZXR400) it works like a charm.

Together the systems won't work. Motogadget replies to me that it's a compatibility problem. Advise to use the inductive signal pickup. Problem is the 3 sparks before mentioned.
My reply was what are the criteria to be met to be compatible....

If figured, I can't be the only person who has a Power Arc system and Motogadget tach.
Anyone out there knows anyone, who knows anyone that got these working together? It must have something to do with the signal I guess.
Hope someone can provide some help.

Kind regards,

Herbert.

[calj737]

I use a C5 (based on PA) with a ChronoClassic and no problems. Are you using their Ignition Signal Pickup? Its designed for use with CDI ignitions, but it may solve the problem. Also, reach out to PowerArc and inquire whether their plug wires are "suppression type". Also, be sure to set "impE" and "impF" values correctly.

The MotoScope Pro was targeted at track bikes, so its pretty full featured with more inputs than their standard product.

[h.lanooy]

Thanks for the reply Calj737,

My system is also from C5. Plug wires are supression type (moroso 8mm).
Also using resistor plug caps.
Both Paul (C5) and Gary (PA) never came across this problem before.
Both take time to come up with solutions.

The induction pick up mainly used for cdi picks up the 3 sparks.
Can't find the right setting for it to give the correct rpm reading.

What impE and impF did you use on the chronoclassic?
Did you hook your chronoclassic to the PA green wire tach trigger?
Or did you use the motogadget induction signal pickup?

[calj737]

I used the Yellow wire on the Chrono wired to my coils, but I don't recall the impE and F values off the top of my head. I wonder if the MScope can be compatible? Did you inquire with MG directly as to whether there is a variable to adjust for 3 impulses?

I'm curious now, because I was considering using this gauge on a pending build with a C5, so I am glad you are being the Lab Rat 

[h.lanooy]

So you did not use the pa module green tach pulse wire?

To which wire of the coils did you connect the chrono's yellow wire?
What type coils does your c5 system have? My set has the newer mc2 coils. If I connect the motoscopes yellow wire to the yellow coil wire, that coil gets overheated.

I asked motogadget what the requirements are for the signal to be compatible. Still waiting for their reply.

But if have three sparks, you must have made adjusments in impE and impF for it to work correctly.

Could you please check your settings and post it here?

Thanks again!

[calj737]

If I recall correctly, I connected the YLLW from ChronoClassic to the right side coil, which serves 2/3 on my install. I don't recall using the GREEN wire from the C5. I appear to have the newer MC-2s, black coils.

I don't have access to the bike currently as I have it in storage, so my impE/F values are not available. (I had a storm damaged garage and have the bike stashed away until rebuild is completed on my garage.)

[h.lanooy]

When I tried your type of setup, no mather which coil, it gets overheated.
Can you recall not using 1 as your impE?
If I use impE "1" I definitely get too high rpm values. If I use 3 it's still not right. This is by using motogadget's signal pick up.

I'll keep trying different settings.
When you have access to your bike in the future please check the settings and let me know. There's a chance I won't find the correct settings.

[calj737]

what component gets over-heated when you wire directly to the coil? The gauge? The coil? The gauge should be wired to the NEG side of the coil (trigger wire from ignition plate).

[h.lanooy]

The coil gets overheated.
I connected the yellow motoscope wire (tach trigger) to the yellow coil wire (trigger / negative side).
I could try making the connection to the black or white wire coming from the module and not the yellow from the coil.

[calj737]

Don't do that. Their gauge definitely does NOT want voltage sent across that signal wire.

There should be no effect on the coil from the gauge wire being tied to the NEG side. You do realize, when your key is on, and the bike is not running, the coils are charged already? Perhaps this is what you are noticing?

[scottly]

The Power Arc works with optics timing, more accurate than Hall effect (magnets).

This is pure marketing hype, as fabricated as the animation they use to "prove" it.
 

[h.lanooy]

Problem is identified.

I hooked up the trigger wire from the PA module and the trigger form the induction signal pick up.
When cranking the engine you can instantly see the difference.
Both signals have a 12V strong signal.
The trigger of the PA module drops to about 2V to 3V (never hits 0V!!)
The trigger from the induction signal pick up hits 0V.

With this knowledge I came to the conclusion that this is the only difference why one signal works with the Motoscope Pro and the other doesn't.

I only need to make the trigger from the PA module hit 0V when it pulses.
I tried this with a pull down resistor. I had 3 sizes, 10 kΩ, 4,7 kΩ and 1 kΩ.
Only the 1 kΩ gives a result. The tach from the motoscope reacts to the PA module's trigger!!!!!!!!
But it seems 1 kΩ is too small so the 12V sips away and the signal never reaches the Motoscope in about 5 seconds after cranking.

But the source of the problem is identified!!! I'm closer to the solution.

[h.lanooy]

It has been a very long time, but problem fixed around time I started this post.

The solution for me came from help on a circuits forum. Someone came up with the diagram underneath. It works (on this date at least 2 years).



I hope in someway anyone running into the same problem is helped by this.