Cursed Gamma?? No Spark

[gammadave]

Hi All, im new but straight in with a belter for you to ponder,

i seem to have got myself into a bit of a pickle,

I am in the process of building a 1986 Rg125 Gamma, i am at the stage where the bike is built, on its wheels, engine in, new loom, all lights indicators etc working, But no spark! this is where i am upto,

2 ignition switches (1 nos)
5 ignition coils (3 nos)
3 CDI's
3 looms (1 nos)
3 Generator & pick up coils (1 nos)
3 new spark plugs & caps

When i kick it over there is no spark at the plug but when i remove the coil wire and go to put it back on, it sparks against the connection?? i really dont know what is going on, the frame is powdercoated but all earths have been ground to bare metal,

i know it can only be something ridiculous but finding it is getting expensive now, i have replaced everything! i think its going to be something so simple and rudimentary that i will probably be humiliated when it is pointed out,

i do have the original workshop manual & fully equipped toolbox,

Any and all help and advice is highly appreciated,

Thank you.

[stinkwheel]

Well, instead of guessing and swapping parts, test.

Multimeter set to measure resistance and start checking continuity/resistances.

You have a manual so check the primary and secondary winding resistances on your coil.

Now attach it to the bike, plug it in and check the LT side again. Is the resistance the same or is something earthing it? (that's how most kill/ignition switches work on bikes of that era, by earthing the LT side of the coil).

Ok, how about continuity? Check all the things that should be earthed have good continuity to the battery negative. So the engine itself, the CDI, the frame.

Is there continuity between the HT lead and the end of the plug cap (there will be a resistance equal to the plug cap).

Idiot switches? Sidestand? Clutch switch? Neutral light working?
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[-]

Have you got the low voltage wires to the coil back to front? It the HT lead definitely fixed into the coil properly?

I'd go for sidestand switch but if the coil is sparking when you go to remove/connect a low voltage wire?
____________________
TZR250 2MA road, TZR250 1KT road, TZR250 2MA race, TDR250, YZF-750R Boost colours.
Jaguar S Type 3.0 V6 Sport R, VW Transporter T5 GP LWB Shuttle 140ps DSG.

[WD Forte]

Yep, you could have bought a really good meter cheaper than all that
swap and hope stuff.

The lights probably work because they have a ground lead in the harness connected to battery neg.
Ignition might have but often relies on physical metal to metal contact
between case and frame
I'd check ground continuity between the battery neg terminal
and frame, coil mounts and engine case.

You could alway use flying leads between the engine case, coil mount and battery neg to test and see if there is a continuity problem
____________________
bikers smell of wee

[gammadave]

Thanks for your responses, Appreciated,

i should have added, 2 multimeters as i thought that my first one might be wrong, there is no sidestand switch, kill switch has been bypassed, all continuity seems fine, extra earths from frame to engine, engine to frame, engine to battery,

[RhynoCZ]

There is no such a thing as a cursed motorcycle, only incompetent mechanics. Well, the Vampire motorcycle was cursed, but the film was not a documentary, so I assume it was only a work of fiction. I still don't trust any of the Norton Commando bikes, though.

For those, who question my sanity: https://en.wikipedia.org/wiki/I_Bought_a_Vampire_Motorcycle
____________________
'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[-]

[gammadave]

[-]

And if you leave the wires disconnected, then turn ignition in and try to get a spark?

On similar era 2 strokes, connecting the wires will actually turn off the ECU and therefore spark.
____________________
TZR250 2MA road, TZR250 1KT road, TZR250 2MA race, TDR250, YZF-750R Boost colours.
Jaguar S Type 3.0 V6 Sport R, VW Transporter T5 GP LWB Shuttle 140ps DSG.

[gammadave]

[stinkwheel]

There are what 6 wires on the CDI? So it'll need 6 wires to run. I'd make up a jury rig loom to confirm all your componants are working.

Not familiar with your bike but I'd imagine those 6 wires are live, earth, to and from pulse coil, feed to ignition coil. Not sure about the 6th? Pulse to powervalve?
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[WD Forte]

[gammadave]

[salem1987]

On my gamma it would not spark due to there being two black with red tracer wires from the cdi which were the wrong way around.

One going to the kill switch/ignition and one to the stator/alternator.

Swapped them round and it sparked.

good luck

[gammadave]

Right ... Update!

Derek Acorah has been round and done his bit and it is now sparking!

Well actually ... i stripped a loom down to just the ignition system, then went through everything on the bike wire by wire, comparing and testing, Then i swapped ignition coils, fresh plug, fitted the pick up coil correctly and it fired straight away.

The eagle eyed readers may have noticed i mentioned 'fitting the pick up coil correctly' well admittedly i has completely missed the second hole on the pick up coil and put the screw straight into the hole,

Didnt someone mention incompetent mechanics earlier?? lol

[-]

Probably one of those "can't see the woods for the trees" moments, where a fresh set of eyes could have spotted it long ago.

Glad it's firing eventually and you know a bit about RG125 ignitions now!
____________________
TZR250 2MA road, TZR250 1KT road, TZR250 2MA race, TDR250, YZF-750R Boost colours.
Jaguar S Type 3.0 V6 Sport R, VW Transporter T5 GP LWB Shuttle 140ps DSG.