R25/3 -54 will not charge...damned red light!

[FelixM]

Switch in 4th gear and put on the brake (or jam the rear wheel by other means).

Thanks, Rütz! Great advice! What about the pulling tool? Can I expect the local car tool shop to have it?

[FelixM]

[Borgward]

No, but you can easily build it yourself:
just take a M8x90 screw and remove (file) the lower part of the thread as shown in your picture.

Hubi

[Kurt in S.A.]

Doubt a local car shop will have the pulling tool.  I've bought them here in the US.  They must be hardened steel.  If not, they will bend inside and you will have a bad trying to get the rotor off.

Kurt

[Borgward]

not necessarily - I use an unhardened screw with removed lower part of the thread for more than 40 years now - no problems ever.
but one can harden the screw of coarse to be on the safe side

Hubi

[FelixM]

Hmm, ok, so a M8X90mm will do. And the remove the thread - how many mm's? I screw it in, and then? Pull? Tap? Not really sure and I really dont want to damage the crank shaft...I feel Murphys law is strong here!!

[Borgward]

Hmm, ok, so a M8X90mm will do. And the remove the thread - how many mm's?

take away about half of the length (i.e. 40 - 50 mm). It must be possible to slip an M6 screw nut over it.

to remove the rotor you only have to screw it in tightly, this will push the rotor off

Hubi

[FelixM]

take away about half of the length (i.e. 40 - 50 mm). It must be possible to slip an M6 screw nut over it.

to remove the rotor you only have to screw it in tightly, this will push the rotor off

Hubi

Hi Hubi,
Great! So, I slip the M6 nut over the M8X90. Insert it as far as it goes and then start tightening the M6 so it pulls in the M8? And thereby pulls out the rotor?

And the new rotor - just push it on?

[FelixM]

Here they talk about M6X55 and I don't understand the illustration. Is the /2 different? The more I look into it the confused I get.
Could someone please do a step by step instruktion...

[FelixM]

Ok, I got some stuff from Uli's (including a pair of gloves! Thank, you!)
1. The Fliehkraftregler is _much_ stiffer in the springs than the original. I suppose thats ok?
2. The rotor has quite some friction when I rotate it by hand in the Lichtmaschine (Anker?). Does it wear down when it is used?

[4Taktix]

Moin Felix,

1. hard to say - in any case they should reach outer position at approx 3000 rpm ( can be checked with a strobe-gun )
2. the rotor must not touch the field-coils or their cores. There has to be a small gap in between. Check with a sheet of paper/
    check for scratch-marks.   Did you tighten the 4 Field-coil bolts thoroughly ? And also the Dynamo-case screws to the crank-housing ?
    There must not be any slight gap between Dynamo-case and crank-housing. Rust, Paint, burrs and stains must be removed thoroughly
    before attaching Dynamo-case.

Concerning your understanding of how to fix/remove the rotor from the crank, I quickly made a little sketch for better understanding.
The Rotor is fixed by a longer bolt which is threaded only ~ 15mm at the tip. The Rest of the shaft has no thread and is smaller in Diameter.
The Tip-thread sits in the crank ("Thread 1" ) and fixes the rotor to the crank-taper.

To remove the rotor, this bolt has to be removed - it will come lose when leaving "Thread1", then you can pull it out a bit, then you have to unscrew again
to get it through "Thread2".

Now insert an appropriate Steel-pin (the harder the better) which has to go in up to the ground of the crank-thread ! ( "Thread1" )
(Shown in blue in the sketch)
If you now screw in the bolt (any M8-bolt will do) through the rotor-thread ( "Thread2" ), it props against the steel-pin and so presses the rotor off the taper.
Does it get clear now ?

Regards,
Sascha

[Borgward]

Felix,
sorry,it should read M8 nut instead of M6 (damn typo)

Hubi

[FelixM]

Hi again,

Thank your Sascha and Hubi!

I have to admit I just checked by inserting the the rotor by hand in the stator/lima and found it tight. Probably just tight tolerances so it will move freely when mounted...

Ok, I get the thing now with pulling the rotor off. I could use a shorter M8 (found 50mm at the hardware store) and use a non threaded pin in smaller diameter in the bottom. The effect will be the same.

And the new rotor is just pushed on the crankshaft? (Before the bolt is mounted as the last step, through the Fliehkraftregler?

At the moment I'm busy with my old Alfa GTV (105) but will have a go at it soon. Luckily holiday starts next week sp I have time to ride. 🙂

[FelixM]

Doubt a local car shop will have the pulling tool.  I've bought them here in the US.  They must be hardened steel.  If not, they will bend inside and you will have a bad trying to get the rotor off.

Kurt

Hi Kurt, Greetings to Texas from Visby, Sweden!

I've checked the cheap hardware stores to no avail and will go to the expensive one tomorrow!😀 Will go for a M8X90MM and grind away the threads on the end.

[OldsCool!]

Ok, I get the thing now with pulling the rotor off. I could use a shorter M8 (found 50mm at the hardware store) and use a non threaded pin in smaller diameter in the bottom. The effect will be the same.

Yes, that will do the job. But be careful about the pin. Must be hardened steel so it will not bend. If it does and gets stuck inside, that's it 

BR

Steffen

[4Taktix]

Hi Felix,
why so laborious ? If I were you, I'd simply cut off the shaft of on old/dull 7mm drillbit and use that.
Consider the rotor has an M8-thread at the frontend, so if you use a threaded M8-bolt, you will have to screw it through there.
How will you do that without a hex to put the wrench on ? And if you slot it for a screwdriver, this slot will very likely be damaged after pressing the rotor off.
Keep Things simple ! 
Or was it meant to use a "one piece bolt" long enough with just the threads removed on the tip ? Ah OK. That will also do.
Be sure to remove enough thread length then.
I'd say a drillbit-shaft is harder than a stock 8.8 bolt. But I have no proof, just estimated from experience.

Regards,
Sascha

[berndr253]

I made bad experiences with the solution Sascha wrote about above.
Try to get a professional tool

Regards

Bernd

[OldsCool!]

I would say it depends on the condition of the setup. If it is completely stuck and oxidated together for 60 years, probably Bernd is right... that could go wrong given the force to be necessary. In my case (even also min. 40 years of stand-still) I got the rotor off with a piece of hard-looking steel with no issues.
But, we have warned you, so make your own conclusions and go ahead

BR

Steffen

[FelixM]

Hi guys! Today I started Operation Remove Rotor! And...it's still there...
I tooled myself a m8x100 or so Rod (se pic) and it went all the way in. But the rotor didn't move one mm...Either the crank shaft is deeper or I have just made a hole in it...
What's going on here??

[FelixM]

I measured the depth - definitely more than 90 mm!

[Eppo]

Hi Felix,
for my /2 I made a similar tool,
length without head is 96mm, with approx 45mm with M8 and a flat end.
It had just the right length, some mm lesser and it was too short.

[FelixM]

Hi again folks! At last! Entlich! Äntligen!

Luckily I bought a rod at the hatd ware store so I could make a longer version. With ca 70-80 mm of smooth surface (wear safety glasses!) the rotor was loosened with a snap. I used som wd40 the night before.

I will save installation of the new rotor till tomorrow...