Topic: CB400f alternator fried?

[strynboen]

have the battery been reversed?

[Baune]

No it haven't and the rectifier should be working correctly so i guess no power could travel to the stator?

[Baune]

Okay, so after buying a new stator, i started trying to find out why the rotor was rubbing against the stator. Well one of the threads was broken which meant i couldn't tighten down the cover sufficiently, and one of the dowels were indeed missing as pointed out earlier. I bought a new dowel from a local dealer and fixed the thread, but even though i minimized the rotor touching the stator it still does. Any suggestions as to why, and what i can do?

I was thinking of putting the rotor in a lathe and then take maybe 0,5 millimeters off in diameter, just enough to make it clear of the stator, any problems with doing this?

[strynboen]

can somone have crunched it vith a tube vrench..and make it ovale..po"es can do all kind of strange Things.

you can turn it a bit dovn..but then there vill be a bigger airgab..and the magenet flux vill suffer a bit..but dont think it vill be messuarabel..
i vork in a elektro motor shop...and ve grind lackqer and paint of stators inside. but never of the rotors...try to take as littel as possibel...ve have never had a stator vho lost funktion..by air gap....but dont take morre then 1 milimeter..better to try to straighten the bend part...it can be cleary seen in the lathe..to find the heigest spot...and press it a bit inn,,and pull the lovest one aut..

#$%*..du er fra Svendborg..jeg er fra Langeland...jeg har en ekstra krumtap..med rotor..du kan få den rotor..har også drejebænk og alle værktøjs maskiner..hvis du skal have beabejdet nogle dele

[scottly]

Before turning down the rotor, you should identify the cause of the rotor rubbing; this is Not normally an issue. There is about 0.5mm clearance between the rotor and the stator, IIRC. If the cover is now mounted properly centered, and the stator is still contacting the rotor, check to see if the rotor is running true, or if it's out of round as Lars mentioned. If it's round, but not running true (wobbling), it may be bent or improperly mounted on the crank, or worst case the crank may be bent.
Look at the rotor; is it showing wear in just one area?

[Baune]

I wasn't able to find out why it is rubbing against the rotor, but i did just go ahead and turn it a little bit down. It is charging now and im a happy camper! Only thing left to find out is how much the generator will output now, and that i fortunately very easy.

I thank you all for your help and advice!

Best regards

[PeWe]

Important to assembly the rotor correct. I have only done CB750 where the rotor sit tight in the alternator cover. It must sit flush and holes for the M6 bolts are formed when it sit absolutely correctly turned. Let it in with soft fingers, not banging it to sit that will most likely cause burrs and it will never sit right. Make sure that the surfaces are smooth and even. Remove burrs with something sharp ad a knife. Finish with grinding paper.
With correct angle stator will fall into its correct position.