67 Daytona T100r No Spark Help!!

Have you got a multimeter? I would be double checking all your wiring and doing continuity checks on both +ve and -ve sides of the low tension circuits. I would be more reassured if they could spell ‘capacitor’ in their ‘destructions’.

 

@D'Ecosse

 

https://www.triumphrat.net/threads/electrical-cunundrum.972095/#post-2004085542

StuartMac
Moderator


Hi,

chazdo said
Micro IV
When I touch the stator wires together no spark when I touch them release them nothing
To be clear, the wires that should be touched together for this test are the Black/Yellow and Black/White out of the "Transistor Box" ... the Stator is electrically inert when it's disconnected from the Transistor Box.

no voltage at all on the black wire going to the first coil in series. Shouldnt I have something?
Depends. Ernie (Bransden) incorporates a jolly little jape in his Transistor Boxes for twins (and singles) ... Once the Box is powered up from connection to the battery (turning on the ignition switch usually), if it doesn't 'detect engine movement' (i.e. Volts and Amps changes caused by the Rotor being moved past the Stator magnets) within a few seconds, the Box powers itself down ... it powers up again either when 'engine movement is detected' or if it's disconnected and reconnected to the battery. Ernie's always reckoned this 'feature' is to stop the coils draining the battery ... in a few seconds? One might wonder why B-B Boxes for triples don't have this 'feature' ...

To beat the 'feature', when the Box White wire is connected to battery -ve, all the EI and HT connections must be made already, at least one plug out of the engine and visible and the Box Black/Yellow and Black/White wire ends should be held together already ... Only then if a stream of sparks at the plug is still not seen is it likely there's another problem ...

Chazdo
two new coils
primary resistance on both coils is 5 ohms 10 in series.
Boss Emgo manufacturer says will work with 6 or 12 volt system
No, they won't ...

Ignition coils on these old heaps were triggered by points before '79. The primary criterion of any DC coil triggered by points is the coil draws between 3 Amps and 4 Amps when its rated Volts are applied across it; this applies whether a given coil's rated for 12V, 6V, 4V or 3V.

The Volts and Amps are linked together by a coil's primary resistance (Ohms), specifically Ohm's Law - Volts = Amps x Ohms.

So, if any coil's going to draw between 3 Amps and 4 Amps, the primary resistance cannot be the same for both 6V and 12V - specifically a '6V' coil must have a primary resistance between 2 Ohms and 1.5 Ohms respectively, whereas specifically a '12V' coil must have a primary resistance between 4 Ohms and 3 Ohms respectively.

Most EI for these old heaps is 'points replacement'; i.e. it just replaces the points (and auto-advance); risking labouring the point, they use the same coils as points ... Note neither of the ranges above include "5 ohms", because that cuts the current draw to 1.2 Amps if 6V is applied across it and 2.4 Amps if 12V is applied across it.

Cutting the Amps draw of any ignition coil with high primary Ohms is a crap idea - slows the HT charge time and, if that's limited mechanically - points auto-advance or EI trigger unit - as rpm rises and dwell time falls, eventually the coil won't charge fully between sparks, meaning you'll get a crap or no spark ... As you've noted, individual component resistances connected in series are cumulative, so 10 Ohms will allow just 1.2 Amps to be drawn ... to charge two coils ... mmm ...

Aside, Ernie Bransden (Boyer-Bransden) does continue to maintain twins can use '12V' coils in series and triples can use '6V' coils in series. However, from personal first-hand experience, if you 'phone B-B tech. help ("'phone" should give you an idea of how long ago this was ...) seeking help with a malfunctioning EI, one of the first questions certainly used to be, "Does the bike have 6V or 12V coils?"; if the answer was, "12V", the immediate advice was to fit 6V ... Wisely ime, most other EI makers advise just '6V' coils (on a twin) ...

Some contributors might post they're using '12V' coils with EI on their twins without problems; however again, I'm pretty certain none will post they're using two 5-Ohm coils in series ...