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Subject:capacitor fix mitigated buck, did not fix
From:Warren Lail
Date:Sun, 16 Jan 2005 16:11:40 -0600

Hi all,

Maggie and I made a safe and fun trip to New Mexico (1200 miles roundtrip) and Bill Bones performed well,
sort of...

The dreaded bucking syndrome began so I stopped and soldered in a 15 volt 22 microfarrad tantalum
capacitor that I got from listmember Tom Miller.  I connected the positive side to number 2 and the negative
side to number 4.  Interestingly, the idle that had always surged, was now stabilized.  The next 50 miles
were a joy.  No bucking at all.

However, after about an hour on the road, just when the bucking normally begins, I got a diluted version
of the same thing.  It appears that the capacitor stores energy or something like that, and when the system
needs it it is returned (not sure about this).  The result was that instead of a bucking jolt like I normally get,
I got a slow loss of power, and then a return surge.  It is as if the capacitor is almost powerful enough to
remedy the situation, but not quite.

On the return trip, I got behind the bus and smelled the exhaust.  It seemed to have that smell associated
with a lean engine.  Not wanting to burn anything up, I disconnected the capacitor.

Of course, the original bucking returned, as did the high idle (1800 rpm after coming off the Interstate).
The high idle is never a problem around town.  It only occurs after extended driving on the Interstate,
and accompanies the bucking behavior.

Several questions:

1.  Is the capacitor really a fix or just a band-aid?
2.  If it is a fix, what did I do wrong?  If a band-aid, what is the real cause and how can it be remedied?
3.  Will a new AFM solve the problem?
4.  Is the factory pigtail a better fix (albeit a more expensive one)?

As always,  thanks for your help.

Warren Lail
88 Westy "Billy Bones"

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