Intermittent miss

I'd still have a look at the ign. switch. Maybe just undo it and let it dangle so it isn't shaking with the harmonics that run through the bike when running.
 
If a diode is buggered, you may find that the alternator output has a lot of electrical noise on it (AC leakage) - the Ignitech may be objecting to that - as well as a reduced charging output.

So Cam's on the money!
 
+1. If the sucker drains the battery at still stand, one or more of the power diodes could be shot, or the integral regulator circuit sitting inside the alternator (commonplace on today's units) has a defect. Usually modern day alternators have added two diodes connected to the star point of the stator winding, providing additional output at alternator speeds above 3000 rpm. That might be the reason why the intermittent misses are disappearing when you are bringing the bike to higher revs. Depending of manufacturer and type of alternator, I wouldn't hold my breath that spares are easily available or homemade repairs being possible at all.
 
I was misled by the title.
I thought Chris may be occasionally cross dressing...
:P
 
I'd start with your first instinct, not about clothing, about the charging situation and not enough grunt to run the ignition.

I'm always a fan of fixing the obvious stuff first....
 
It?s a 270 motor isn?t it? Ignititech using a channel for each side, do you know which side is playing up? You could swap the channel and coil used for each side and see if it changes sides. Does it only do it under load or revving in neutral? Try it with a strobe if it plays up in neutral.
 
so its a twin, albeit twisted, but with an alternator? quite a rare bird that then, 19,680 of them had dynamo's
which makes DC not an alternator which makes AC
CLEM
 
Why live with a compromised alternator, Chris? Mine is an ND from a large Kawasaki. I run it at 1.75 x crank speed via a Gates belt. Never had an issue - if I do, I'll replace it - $140 from wreckers. Initially, some work to fit weather shields and alloy weld a bracket ... replacement would be innards only. I won't be using teeny weeny batteries with it either.

I like Tippie's idea as well. Isolating the prob is close to resolving it. The theory about +3000rpm alternator output increase is also sounding promising. I pray that my Ignitech sys is reliable (hundreds of people using them without issue) - the early ND elec ign off a Suzuki GS I adapted, retaining the mech advance, and used for 20 years never missed a beat.
 
Don't worry about the reliability of the Ignitech Quentin. They're pretty indestructible ignitions, even when connected up wrongly, or running with a coil output not earthed (that'll kill some ignitions). They're very tolerant of coil resistances too. They'll drive pretty much any coil you hook up to them. Normal coils are 3-5 Ohms, but I think Red runs 0.5 Ohm coils on the race bikes without any series resistors. Those coils will be pulling pretty high current through the ignition box, but the Ignitech takes it in its stride.

I've not heard of any Ignitech failures, and in my own experience I've found their ignitions to be totally reliable - except for one minor glitch. I bought and installed one on a mate's Guzzi and a found that the tacho output signal didn't work. Ignitech offered to replace it if we sent it back for them to test. But my mate didn't want the bike off the road for the few weeks it would have taken to send it back for them to confirm the fault and then send a replacement. We found another way to drive the electronic tacho (taking a signal from the ignition coil) so the faulty unit stayed put. All other functions worked OK so it wasn't a problem.

I reckon they're great little ignitions, and really good value for money. Especially considering their programming flexibility. There's a couple of things I reckon they could improve though. One is the multi-pin connector. It's a piece of crap in my opinion. The type used by Sachse is better. The other thing is the computer connection. I dunno why they persist with a RS-232 serial port connector when everything these days uses USB. It's hard to find a computer with a serial port, and I've found USB-serial adaptors to be unreliable. If they just made the bloody things with a USB connector, it would make life easier for us users of their ignitions.
 
Does the coil actually pull current from the ignition module? I understood that the ignition unit sends out a very short pulse that the coil then amlifies with it?s resistance. That could be a pulse from a condenser (capacitor?) triggered by points, or an ignition unit of any type that copies that. Please don?t shoot me if I am wrong  :-X
I like your comments about the Ignitech components. I love the unit, have fitted them to a few SFs using the Guzzi type rotor hall effect system, and used to regularly be in contact with them. For the last few years I have had zero response to any contact I have made to them. I had made comments similar to yours, here on the forum iirc, and wondered if they had blacklisted me. I even sent them a letter by post trying to buy a system, without luck.
I think Chris needs to discount that alternator from the equation, as Red suggests, and start systematically fault finding/eliminating. There are enough similar systems he can borrow bits from. Even plug leads/caps can cause shit like this.
 
Tippie said:
Does the coil actually pull current from the ignition module? I understood that the ignition unit sends out a very short pulse that the coil then amplifies with it?s resistance.
Click to expand...

Perhaps "pull" is a misleading word. But all of the primary current that energises the coil also passes through the ignition module. The pulse isn't necessarily short. It has to be long enough for the coil to saturate (when the coil's magnetic field reaches its maximum). The coil may be conducting for more than half the time whenever the engine is running.

It may give you a better mental picture to imagine the coil's normal state as being switched on and conducting current. The job of the ignition system (whether it's electronic or mechanical points) is to switch it off at precisely the right time. It's the switching off that collapses the coil's magnetic field, which induces a very high voltage in the secondary winding of the coil and makes the spark. Once the spark is over and done with, the coil is switched back on and its magnetic field begins to increase again. The building of the magnetic field takes time. That's the "dwell" time that you hear people talking about.

The coils are fed by a positive wire from the battery (via the ignition switch). The wire from the negative terminal on the coil goes to earth via the ignition module, so a circuit is created and current flows. The ignition module interrupts that to earth connection at the appropriate time to make a spark. But while it's conducting to earth (during the dwell phase) the current is flowing through the semiconductor switch doohickey inside the ignition module. With a 3 Ohm coil fed by 12V, the instantaneous primary current flowing through the coil and ignition module is 4A. But with a 0.5 Ohm coil, the current is 24A. OK, it's an intermittent current with roughly a square wave pattern, and the RMS (think average) might be half that, but that's still quite a high current for an semiconductor.

I suspect Red went to 0.5 Ohm coils to reduce the dwell time required. With a high resistance coil at high revs, there may not be enough time for the coil to build its magnetic field between spark events. A low resistance coil will cycle a little quicker. I recall something about his race bikes missing at high revs with higher resistance coils.

PS: I've tried to keep it simple, but the electrical theory purists might argue that I've only considered resistance and not impedance. I'm aware of that, but my argument is that once a coil has saturated, The reluctance part of impedance falls to zero and the circuit can be modelled as DC rather than AC.
 
Well, after finding the key to the bike..... remember this not a Lav loom, I removed the plug from the stater soliniod and there is a power terminal there that, even with the battery isolated, my 12v test light had a slight glow between the terminal and battery earth..... ignition of lot on I still had still had a faint glow.

While away, the earth to frame, which comprises of, battery neg, ignitech to earth and loom to earth screw had come loose. So we replaced the screw with one that actually grabbed the nylon of the nyloc nut.

So, I started to undo the tape on the loom at that point and found a shit load of unsheathed/melted copper earth wire. A length of about 40mm was adhered (melted into) to the led flasher return wire.

I ran out of time to retest the circuit, for a short after prising them apart.

But now it has me wondering if an LED flasher unit is one directional.

If not, perhaps this was the cause of the dreaded leak to earth.

Or could the short to earth still be elsewhere?

Now to figure out if that leak to earth could have upset the Igntech.

PS: I?ve discounted the alternator diode, as it actually metered well.
 
LJ said:
Two up and cosey on a TS1200 looks even nearer Maurice :LOL:
Click to expand...

No way Lemon, I heard that Maurice has a hump seat fitted for the trip .................. I'm not going to be that close and personal to Maurice, his past history of backing into things would have me questioning every 'accidental' bump  :-\

Meanwhile ....... back to the wiring.





 
Seems to me retrofitting LED lights to our old clunkers is not really worth the effort, IMHO. Bit too hipsterish for my tastes ;).
 
I was impressed at how well they worked, I followed Chris well both Chris,s for more than 50ks while there left blinkers blinked away. Seriously those tiny LEDs worked very well and could easily be seen and turned off you could hardly notice them.I wonder if not having a couple up front had something to do with the melted wiring? I have no clue.The only similar to this thing I have had was on my 76 Bonnie, I removed the alloy section of airbox on it and bolted some gadget directly to the frame. After finding 300mm of earth wire melted I discovered this gadget was a Zener Diode and it needed to bolt to that large alloy airbox to use it as a heat soak to dissipate the excess power charged to heat. Older models had a finned cover bolted on to do the same.  Who knew.So excess power or excess heat in these wires from something.
 
Don't need Battery with a Zener and a Kick Start or a Buxom Bar Maid to give you push
;o)

Both my 69 Bonney and 70 Trophy had Zeners - Missed it with my 70 750 SF when the Battery was DEAD ;o(
 
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