No Spark!

[nicbrrghs]

Hi,looking for some advice,

The bike started running erratically and lacking any power eventually dieing with no spark at all.

I have changed the coil pack and still only sparks intermittently, on pulling the side cover of the left of the bike I noticed a lack of a gasket and that a lot of crap/dirt had got in.l

Could this be the cause or does anyone know better?

Got one of the lambretta coil packs of ebay on advice from a forum seems okay. I have a yellow wire which isnt connected to anything at the moment.

What size flywheel puller do i need i have already got quite a collection but not small enough for this.

Thanks in advance for any help or advice.