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Bob UK
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Posted From: 94.197.120.29
Posted on Tuesday, 03 March, 2015 - 06:51:   Edit PostDelete PostView Post/Check IP

Many think that the centrifugal advance needs to accurate. This is incorrect.

This is because the centrifugal advance works on rpm and not load and rpm.
It cannot therefore be correct and is only loosely nearly right.
The curve is a guess because of this and then we have how the car is driven.

All petrol engines have a maxi mum spark advance of 35 degrees.

At 1000 to 2000 rpm most car engines will not advance any more.

I had a 500 single cylinder AJS bike and to start pull the advance back to 0 tdc then advance 10 deg for idle and once over 1500rpm full advance of 34 deg. Any more and the bike vibed a bit. From 1500 to 5500 the advance is at maximum.

The two springs are sometimes different to each other. They last for years. But they are cheap
But if overhauling a dizzy and springs aren't available using the old ones is fine.

(Message approved by david_gore)