I hate electrics !

[TS1-200]

I am rebuiding a Lui 50 and can`t get a spark, there seems to be a healthy amount of power coming out of the stator, the green wire, I can get a weak spark without the HT cap just earthing out the HT lead but not enough to jump a gap, let alone a spark plug gap.
I have tried different coils but all the same , any ideas before I throw the lot in the Thames

[coaster]

Obvious one first, have you tried a new HT lead? What condition are the points in? they might need filing at least or renewing. The capacitor is a vital component too, I think it stores one of the pulses and both are then deliver when the points open (or is it close ) Anyway, if it's feked it could account for a poor spark as you will only be getting half the voltage. That's my understanding anyway If I'm off the mark then perhaps J1MS will be kind enough to come to my rescue again (bottom of the Hardnott Pass springs to mind )

[Adam_Winstone]

Got a decent engine to frame earth?

[TS1-200]

Got a decent engine to frame earth?

Good point, obvious I know , I'll check that, I have tried a couple of HT leads & coils

[Adam_Winstone]

Is there much pull on the magnets? Old flywheels do lose their strength and it might be that your flywheel is not in tip top shape?

Got a different stator that you could try?

Adam

[Muppet]

ave y tried scratchin yer head then copious amount of cups a tea;

[rosscla]

I'd have thought you should get a big fat spark at the HT lead without the cap.

Also worth to try the wire that goes to the coil from the stator to earth and see what that spark is like.

If you do decide the Thames is an option for you, pop it in the post to me and I promise I'll drop it in the Clyde...honest

[Solerunner1]

I had the same problem on a cento recently. I went from no spark, to a bit of spark, to no spark, etc. I re-checked the points gap, making sure it was spot on, taking extra time on it(on the close side to give extra charging time for the coil) and it fired right up. I don't remember the li range being as touchy on points gap, but then again all my bikes have been electronic for years.

If that's dead on and you've tried several coils and leads, then i would suspect a weak flywheel

[TS1-200]

There seems to be plenty of current from the green wire from the stator, the trouble is I have no Lui stuff lying around to swap things around, it's the 1st one I've done, only doing it for a favour for a mate, beginning to wonder why I let him talk me into it.

[TS1-200]

Sorted, tried another coil, exactly the same took off flywheel thoroughly cleaned points had a good check round, soldered the ring tag on the loom that attaches to the coil, re connected coil and bingo I got a spark, put plug in and a few kicks later she starts up and purrs like a kitten.