rotor shot?

dtkid · Posted: September 28, 2006, 11:29 am Post subject: rotor shot?

Hey Folks:

I measured the resistance of the rotor on my 79' XS650 and it was only 2-3 ohms. Does that mean that the rotor is kaput?

Also, would a bad rotor/stator cause the machine to not want to fire the plugs consistently or would it have no effect since it is on the "charging" side of the electrical?

Thanks for replies: David

jimmer · Posted: September 30, 2006, 7:33 pm Post subject: Re: rotor shot?

Hmmm ... well they say 5 ohm is minimum. I get 3.8 across slip rings and charges fine, so I'm confused as well.

If rotor was kaput and not charging at all ... eventually your battery would go dead and bike would not run ... you need a charge to run, without manually charging the battery.

Easy test I'm sure you are aware is ... does headlight brighten when rev to 2500 or 3000 RPM? Measure volts across battery terminals at idle and rev to 3000 ... should get 14.5 or so DC volts.

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

Actually - 4 ohms is usually minimum - 5 is better. Lower ohms will still charge - just not well. The lower the ohms - the higher the rpm has to be to reach 12 volts or more.

The higher the ohms (up to Cool

the more voltage you get with less work from the engine.

3.8 is probably just on the edge of dying - and even if it works - it's not working as well as it could be.

Jim

jimmer · Posted: October 9, 2006, 3:57 pm Post subject: Re: rotor shot?

Thanks Jim ... I do have a rebuilt one from Custom Rewind on the shelf ... and a puller ready for action. I'll let the existing one live out the rest of its natural life.

dtkid · Posted: October 10, 2006, 8:58 am Post subject: Re: rotor shot?

Man....I got a good rotor on a 72' XS650 parts bike which I cannot get off the shaft. I have tried two prong pullers, three prong pullers, soakin' the shaft with PB-Blaster & Liquid Wrench, heatin' the shaft (& lettin' it cool down).

Any suggestions?? I have also tapped on the shaft and puller prongs with a brass hammer.

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

I bent 2 heavy duty pullers trying to get the rotor off -
Then I bought a $19 rotor pulling tool from Mikesxs -
and it popped right off with a simple twist of a small wrench -
it's the only way to go.

Jim

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