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dizzy points plate return spring....mines broken!

Posted: Mon Dec 28, 2015 10:29 am
by iconic
My Moggies had a cruise misfire that was so bad it screamed 'ignition system'.

....so I had a little poke under my dizzy cap and found the points plate has a broken return spring.

I'm thinking this return spring must be unique to the 1098 dizzy, even may by year I'm guessing?

I suppose any moggy 1098 dizzy return spring will better than nothing as the ignition timings all over the shop?

Any advice welcome gents and ladies.

PS The misfire was......running too lean and I do mean lean. The set point for the carb' jet was wound around 1/2 (.5!) a turn from base setting down rather than the usual 2 turns.

...its amazing just how well this old Moggy ran with one pot with a burnt valve, two others with tight valve clearances, timing a mile out, carb setting way out and more leaks in the air inlet route than No.10 :D

...old cars don't you love them, they will run OK'ish even when on their knees.

Re: dizzy points plate return spring....mines broken!

Posted: Mon Dec 28, 2015 11:36 am
by bmcecosse
By 'return spring' - do you mean the spring that attaches the vacuum advance pod? That is essential - and is same across all the 25D dizzies. You should check that the vacuum advance actually works - once you have a spring connected. Don't worry about the 'flats down or up' mixture setting.... Be guided by the colour of the spark plugs after a good run - they should be 'biscuit' colour. Not brown or black - or white.

Re: dizzy points plate return spring....mines broken!

Posted: Mon Dec 28, 2015 1:19 pm
by iconic
Yup thats the one. My friend thinks he may have a dizzy in his garage for a 1098 along with some other bits and bobs, I maybe in luck.

Re: dizzy points plate return spring....mines broken!

Posted: Mon Dec 28, 2015 5:42 pm
by bmcecosse
You sure it is broken and not just disconnected? It's extremely unlikely to break in normal service.