Hitchcocks Forum

That's what happened to my Series 2 Interceptor today. Fortunately not on the road! I had just fitted the pistons and thought as a last job of the day I'd check through the wiring which I had completed earlier. I was just checking the lights when BANG! and one of the coils exploded. It would appear that it has gone faulty in the last 46 years and didn't want to be woken up. An order is in to Mr H but it's rather tedious to replace as they're not all that easy to get to. Cleaned any wax out of my ears though!

REgards, Mark

ooh heck, I hope the electrics are ok!



may have got moisture penetrated in there!

Simon, you're probably right, that's the penalty of rebuilding a box of bits. You can't easily tell which components are correct to begin with and then there's the question; were these bits working when they were dismantled and have they failed or deteriorated in the meantime? This project was never going to be easy, I knew that when I started but the last couple of weeks have thrown up loads of missing small parts which all add up. The 2 bulb holders for the clocks for instance, just a small item but cost £18 (our Hosts don't have them,) and quite a bit of work to make into the correct wiring loom. Oh well, it does look the business if I say it myself!

REgards, Mark

On closer investigation the exploded item seems to be the (brand new, not from our Hosts,) 2MC capacitor which is part of the batteryless ignition system. These bikes were designed to run without a battery in competition but to be honest I'm not sure what this capacitor does! Anyway, I'll use the original one and see what happens... Oh, and find out why the horn isn't working, I forgot about that when the bang happened!

REgards, Mark

Capacitor replaces the battery as an electrical storage unit and yes they do go off with a thud if the smoke escapes. Well that is what the BSA batteryless system did/does

It was a thud alright! There was a surprising amount of smoke in it as well as a lot of cardboard wadding. Fixed the horn, it was dirt inside the button cap. Now I suppose I'd better get on with "proper" jobs while I have some day off left!

REgards, Mark

Mark, these capacitors are polarity sensitive. If you are using a battery you don't need it just leave it off.

On further examination it does seem to be a polarity issue. The old Lucas capacitor has 2 terminals, one of which is a double spade so I connected the new one the same way. Looking at the remains I can see a spot of red paint on one terminal on both old and new capacitors but it is on the single spade on one and the double on the other. So I think I fried it! I've looked in all the manuals and there's nothing about how to connect it except a warning to get it right. The smoke strongly implies I didn't!

REgards, Mark

Boyer Powerboxes, which of course include a capacitor, will also do this! A.

When Lucas used to make/supply the 2MC capacitor, they had a dot of red paint next to the Positive terminal.