Try - and only try - finding fault with the dizzy cap. The central contact
may have a worn carbon brush causing arcing between cap and rotor instead of
a proper contact. The spring may be worn. It might just need a clean and
when replacing the rotor you give enough of a clean to solve the problem.
Have a look at the metal contacts on the inside of the dizzy cap, is there a
grey coloured surface on the metal? If so, get a small screwdriver / blade
and scrape the contacts clean. The amount of build up there can be amazing
I am in full agreement with Tim as to his reasoning. They should / do not
go wrong. I clean the edge of the rotor against a tyre sidewall (say once
every 5-6 years!), rarely does the middle need cleaning and a single twist
of wire wool does that. If it is an old one they can wear a hole through
the metal to the plastic underneath.
Yes there can be problems with rotors, cracks allowing an electrical short
to the drive spindle, arcing across the plastic etc but it is not a common
failure. To have more than a couple of failures in a lifetime does seem
Is there wear in the central drive spindle bearings? Is that moving about
and creating problems?
One of the more amusing but helpful things to do is the run the engine in
complete (and I stress complete) darkness. You'll soon see where your
electrical problems stem from. It might be instructive to do that first!!
----- Original Message -----
From: "Timothy H. Collins" <email@example.com>
Sent: Wednesday, September 26, 2007 12:00 PM
Subject: [Spridgets] Rotor quality problems
>I don't understand why you guys experience "out-of-the-box" rotor
> failures. Just how do they fail? A rotor is a small lump of plastic
> with a bit of metal. I understand a part built incorrectly, or wear
> after some number of thousands of miles, but how do they fail OOTBox?
> The electricity "should" follow the path of least resistance which
> should be through the metal parts rather than through the plastic.
> Are you really saying that they are built with poor tolerances? That
> seems odd too as if one is out of tolerance then every one of them
> should be OOTolerance. It's such a simple part. What's the failure
> Tim Collins
> 1966 AH Sprite
Edit your replies