Shovelhead charging system

[cyclespun]

1974 shovel, kick only, 22amp system.

My bikes stator and reg. went out. Threw in a new stator and reg. But kept the weak rotor cause I didn’t think much of it. Anyways, bike fired right back up after installing the new cycle electric 22amp stator and regulator.

Now, this is what’s got me tripped up. Tested the battery on my multi meter on the bench and it read 12.5. Battery was at around 12.8 at idle, jumping down a couple but mainly 12.8. When I would bring it up to 3,000rpm. Battery wouldn’t get above 13. Even at higher rpm’s. Thought it was strange but went on with my day. Turned the bike off. Went inside, did a couple thing, turned the ignition on to check lights, left it on for a minute. Then went to kick again. No dice. Battery was dead. And I mean dead. I took it out of the bike, and the multi meter read 2. I tested the battery today and it’s at 8 now. My guess is maybe that rotor isn’t creating enough electricity, so I ordered a new one. And might snag a new battery. My other guess was I had it hooked up wrong but no, I’m A to A and B to B. I didn’t change anything up so has me puzzled.

Anyone have any idea if they think in fact this could be a bad rotor issue?

[JBinNC]

Sounds like a bad battery mostly, but with that out of the way, here's my experience.

Using the earlier rotors on any of the '81 - up, 22A or more powerful alternators will result in low output.

In addition, even on the '76 - '80, 18A system, I have seen low output when using the original rotors. It seems after 35 or 40 years they just lose some of the magnetism. I guess they don't make 'em to last. Also note that on the old ones with the magnets in the nylon ring, there is a spring clip and a tiny roll pin that anchor the ring. If the roll pin is sheared or missing, the magnets will slip inside the rotor when the rpms and consequently the output goes up (or tries to go up anyway).

Yes, you need a rotor, as you have surmised.

Jim

[cyclespun]

Sounds like a bad battery mostly, but with that out of the way, here's my experience.

Using the earlier rotors on any of the '81 - up, 22A or more powerful alternators will result in low output.

In addition, even on the '76 - '80, 18A system, I have seen low output when using the original rotors. It seems after 35 or 40 years they just lose some of the magnetism. I guess they don't make 'em to last. Also note that on the old ones with the magnets in the nylon ring, there is a spring clip and a tiny roll pin that anchor the ring. If the roll pin is sheared or missing, the magnets will slip inside the rotor when the rpms and consequently the output goes up (or tries to go up anyway).

Yes, you need a rotor, as you have surmised.

Jim

Thanks Jim, I’ll keep you guys posted once the rotor gets in this weekend.

[cyclespun]

Sounds like a bad battery mostly, but with that out of the way, here's my experience.

Using the earlier rotors on any of the '81 - up, 22A or more powerful alternators will result in low output.

In addition, even on the '76 - '80, 18A system, I have seen low output when using the original rotors. It seems after 35 or 40 years they just lose some of the magnetism. I guess they don't make 'em to last. Also note that on the old ones with the magnets in the nylon ring, there is a spring clip and a tiny roll pin that anchor the ring. If the roll pin is sheared or missing, the magnets will slip inside the rotor when the rpms and consequently the output goes up (or tries to go up anyway).

Yes, you need a rotor, as you have surmised.

Jim

Threw on the new rotor and everything is good. Charging the battery, holding the charge and battery is optimal! Thank you!