Hello all,

I have found myself a Lucas 25D dizzy off an early 850 (pre 64 I think). The vac advance is stuffed so I want to know if there is a way to convert it to non vac advance? And if so what sort of difference it would make to the dizzy curve and is it a good idea to do this?

Cheers,
Alex

Personally I'd just run it with the vacuum advance disconnected. On your average engine, you are unlikely to notice the difference (my 29D vac advance was inoperative for 6 months before I noticed).

vacuum advance is only an economy device - as long as it's locked off, no biggie

the pulsar dizzys a lot of us run just leave the vac advance disconnected

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So by locked off you mean leave the vac unit on the dizzy but just disconnect it?

Is there away to actually remove the vac unit from the dizzy and still have it locked off? or should i just improvise and maybe screw the sliding vac plate to the one below it. Or something like that anwyay...

Block off the outlet at the carburettor. You can leave the vacuum unit attached to the dizzy but just not connect it to the carby. No need to remove it or disconnect it from the dizzy.

If running SU carb(s) I would fit another vac can to it, it's worth about 5 MPG in economy.
If you want to run a Lucas without one it's best to put a screw through the top points plate into the base plate, otherwise it can vibrate about and vary your timing.
But on a Pulsar dizzy there's no need, they are far better made.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I meant what Dr Mini said....

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