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Lighting and Electrical Things that go ZOT! Ignition components, batteries, lighting and accessories

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Old 04-18-2017, 03:18 PM
crassius crassius is offline
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Default bad rotor after all these years

finally found a bad rotor on a motor that sat for 5 or 6 years - replaced rotor and all was well

motor ran before sitting all those years so sitting may be a cause of that weakness over time
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Old 04-18-2017, 08:04 PM
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2door 2door is offline
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Default Re: bad rotor after all these years

We're talking 'magnet', right? I call it a 'rotor' too but not sure everyone else does.

The magnet is the rotor, the magneto coil/frame is the 'stator'. At least if you use proper terminology.

Easy way to remember between the two. The 'rotor' rotates. The 'stator' stays where it is.

Tom
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Old 04-18-2017, 10:08 PM
crassius crassius is offline
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Default Re: bad rotor after all these years

yeah, it got so weak that it wouldn't stick to my toolbox on one side

got a lot of them around here, so may start storing them as a circular daisy chain to keep them all fresh

somewhere packed away I have a magentizer to restore magnets in 1950s BHT magnetos, but not wanting to dig it out
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Old 04-19-2017, 10:51 AM
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allen standley allen standley is offline
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Default Re: bad rotor after all these years

What would symptoms be for a bad rotor? Weak little spark? Hard Start? I got a bike that simply falls all over itself at the top end. Could a weak rotor do that? Got an NT on it. Tweaked and fussed and messed with it all last year. I run a pocket bike exp chamber exhaust, I stuffed a male battery terminal cleaner into the end for positive back pressure. It Does run better under a load but still seems to fall flat when I wind it up on level ground. Hmm.. Food for thought. Thanks Crassius.
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Old 04-19-2017, 11:33 AM
crassius crassius is offline
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Default Re: bad rotor after all these years

a weak rotor has a weak spark at low speeds - expansion chambers can make more power, but it happens only at certain speeds - the reflected wave always takes same time to reach cylinder, so only scavenges at the RPM that has that amount of time between firings
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