Bad rotor, not charging

[warrenlevihursh]

I wanted to get the bike ridable this weekend for the first time. After getting a fresh battery i fired the bike up and checked to see if it was charging. It was not. So i did some quick testing and found the resistance between rotor rings to be around 3 ohms after subtracting lead resistance. So, i guess the rotor is shot. Should i buy the racetech new one for $100 or send it to get fixed? Anyone know how much that is roughly? Thanks!

 

[pamcopete]

warren....,

Did you do the test with the brushes removed? If you leave them connected the external circuits can influence the reading. If the rotor is toast, then get a rewind from:

Custom Rewind
2014 Pratt Hwy.
Birmingham, AL
35214

800 798 7282

Also, did you charge the new battery overnight per the instructions? If not, then it is no fully charged and you may interpret the low voltage as a no charge condition when in fact its just not fully charged. The charging system on the bike only provides about 2 Amps of surplus current to charge the battery, so it can take up to 8 hours of riding to fully charge a new battery. About the same time as an overnight charge with a 2 Amp trickle charger.

 

[warrenlevihursh]

Yes sir, i tested it on the bike and also off the bike same reading both ways. Ill contact custom rewinds tomorrow and get a quote. I really want to ride this thing!

 

[pamcopete]

warren...,

OK. Did you use the lowest scale on the meter with a fresh battery in the meter? Did you verify the reading with another meter? Try these suggestions before you spend $125 for a rewound rotor.

My experience with new vs rewound rotors from Custom Rewind is captured in a couple of videos I made:

Here is a video of a new rotor on a lathe. Note the runout.

Here is a video of a Custom Rebuilt rotor. Note the runout is almost perfect.

The new rotor will work, but the terrible runout causes the carbon from the brushes to accumulate in the valleys and within a couple of weeks the output from the alternator is decreased significantly. Now you know why the new rotor costs less than the rebuild from Custom. The main reason for this difference is because Custom uses the OEM rotor.

 

[warrenlevihursh]

Thanks Pete, I used the lowest setting. Ill confirm with a different meter before i send it. Im right at 3 ohms no matter how i test it. I think the PO knew it was bad and just slapped it on the bike because i bought it not running. The rotor didnt even have the key on the shaft.