Woe is me! Got no spark, looks like the ignition coil is U/S, showing way too much resistance on the secondary winding (approx 45k ohms instead of more like 6k ohms that it should be. And yes I've checked that it's not a prob with the plug cap or duff lead).
I might get away with it if I can substitute the (good) coil out of the TY175 which won't be here 'til boxing day.
(Or the other option is to murder Santa and blame him).
As far as I can see, whilst the secondary winding ohms are the same, at 6k ohms, the primary resistance figures are quite different for the two coils, 175=4.5ohms and 250=1.7ohms, (though I'm working on third hand info because my Haynes doesn't give figures ohms figs for the 175 which is pretty annoying)!
I'll probably try it anyway when the 175 gets here with the grinning mob, but, has anyone tried this swap? TY175 ign coil into TY250?
(Both are 75-76)

