Alternator chewed itself to bits

[gaffer77]

I posted a bit about this before but need some new help
My Alternator cover was getting hot ,,no unusual noises just hot,
anyway i found one stator i used sat a little proud on the lugs
so i swapped the stator for another ,,but found our UK ones may be different to the usa ones (in part number and application at least)

Anyway after a while it got more than hot and was grinding badly
The rotor was very scored on every surface including field coil

Now i have a complete Alternator that was fitted to a US G model i think,, and i am going to fit it to an SF engine ,,,should be all ok

Anyway problem is the rotor has a light dusting of surface corrosion

So i am asking all the advice i can get on cleaning this up and has anybody had a rotor chewed by thier Stator and field coil before ??

I am thinking my last Rotor which also had a dusting of corrosion must have spun all the dirt off and clogged and caused the heat
(it was clean just not clinically clean when i fitted it)
then it scored more and more badly and ground nastily

Has anybody had alternator trouble like this ??

what is best method for cleaning the Rotor ??

i cannot afford for this new Alternator to go the same way as the last as time is not on my side

Thanks

Gareth

[HobbyMan]

It may not be seated properly. The spindle which the rotor sits on must be absolutely clean apon installing

[gaffer77]

Hi HobbyMan

Sorry my fault,,the rotor that got chewed has been on the engine years and in use until recently ,,i wanted a black Alternator cover from our uk bike ,,swapped the Field coil ,,stator and cover,,i left the rotor in place and all the parts ate each other

I have now got a complete Alternator and cover field coil and rotor off another engine that was good ,,but have a dirty rotor to clean

i don't want this Alternator going the same way now i have changed the rotor (it's not all on the bike yet )

Just wondering best ways to clean up a rotor before use

Thanks ,,,,,,,,,,,,,,,,,,,,,,, Gareth

[TopCatGr58]

Hey Garreth,

I had a nice layer of rust on my rotor...heavy metal round vented thing bolted to the crankshaft. I used a wire brush on a drill to scrub most of it off. The rotor is not supposed to make contact as you know. I was going to remove the inner coil from the case once, but then saw that there is a lot of room for positioning the inner coil and so I left it in place. The one screw/bolt I removed didn't want to tighten, stripped, just put some lock tite on it, has held for 7 years.

What I'm getting at is that perhaps when you put the first one on, that the inner coil wasn't as well centered as it should have been and that's what started the self distruction!?

I don't know what technique to use to help you ensure that the inner coil is well centered with clearance when you put the new one on, so perhaps an electrical guru or someone with experience with this will chime in!?
T.C.

[randy]

It's been my experience that the center (field) coil only goes in one way, it centers itself with three bolts. I think the only way to muck it up is if you dont seat it fully in the cover and it's sitting 'cocked'. OR, if you don't tighten the bolts fully and it loosens itself!