Tom, I just let the plugs dangle and ground out on a fin and tick it over. If it's not out in the sun you should see a good blue white spark.
Or you can just stick yer finger on the electrode

2005 Model . Two Fast Eddy stickers , a bell and a clock . She's Lola . She tinkles and keeps time . http://s649.photobucket.com/albums/uu211/britbike05/