Topica Loopframe_Guzzi Archive


Subject: Re: loopframe spark

Author: William Dudley

Date: Aug 13, 2000, 7:36 AM

Post ID: 1701876094



Dave Otis said:

 The condenser stores up an electrical charge while the points are closed and
discharges it when they are open to produce the spark in the secondary coil
windings. If your condenser is toast, you will not fire.

While Dave is normally the person I would ask about Guzzi questions, in
matters electrical I must assert myself and offer a correction here.

The condensor's role in the ignition system is not as stated above.
While it does store a charge, the primary purpose of the condensor
is to control the amount of arcing at the points, so as to minimize
the material transfer from one point to the other and prolong point
wear. If the condensor is an open circuit, then you will see a very
large spark (arcing) across the points when they open, and very quickly
a large divot will appear in one point, and a corresponding bump
on the other one, as metal is transferred from one point to the other.

If the condensor is shorted, then there will be no spark ever, since
effectively the points appear to never open.

Therefore, if your condensor shorts out and you absolutely need to get
the bike running, (like to get off the Queensboro bridge) remove the
condensor. Your points will wear quickly, but you will be able to
ride a little while until they do.

The energy storage in the ignition system is actually in the magnetic
field around the coil. When the points are closed, the magnetic
field builds up, and when the points open, the magnetic field collapses.
It is this rapid collapse of the magnetic field that makes the spark
on the high-voltage side of the coil and hence a spark at the plug.

Bill Dudley
72 Ambassador
71 Norton Commando 750
74 Benelli Tornado 650S (for sale!)
and a whole bunch of Hondas

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