Need some input on removing a stuck armature. I have an AT3 and removing the armature went without a hitch after I acquired the proper puller. I also have a Twin Jet 100 that I am restoring. I thought the AT3 puller would be the same for the 100 but not so. The Twin Jet puller has a different thread and these are like moon rocks to find.
I made up a puller and no luck removing it. This is the second Twin Jet engine that I have not been able to get the armature off. I gave up on that one.
This is a good engine so made the decision to cut the armature off. I have removed as much material as possible and tried lots of heat and cursing but still no luck. I am mindful of damaging the crank.
Has anyone out there had any luck cutting an armature off? I know it sounds drastic but I see no other option. Thanks for any input.

What thread is on the Twin Jet? I know they used 3/8" instead of 10mm on some of the models.

It's a 10x1.5 mm JIS thread. The AT3 is a 1.25 pitch.

Is it a generator electric start system as ours were alternator kick start only models down here, so different armature. If it 'is' 10x1.5 you could get a high tensile bolt from an engineering store & should push on the crank end to pull it off [wild guessing on my behalf].

That is what I did and no luck. Way past the puller option. I have removed a lot of material from the armature to get near the core and used my very powerful heat gun. This thing does not want to budge. It is a YL1 Electric.
Any thoughts out there about careful use of a torch to cut it off ?
Why do I need to get the armature off ? At minimum, to replace the crank seal. This engine has sat for a long time. May go all the way and split the cases.
HELP!!

Jet / can you post any pictures of it ? Perhaps there is a way to weld steel on what’s left of the armature and rig up a bolt to push it off ???
Heat gun is OK sometimes but other times need a quick hit of oxyacetylene to expand one section before the other even knows heat is being applied

I once owned a YD2, and had a similar issue. I ended up, screwing a bolt in the center of the armature and I softly used a slide hammer.
Good luck

One of the Yamaha parts books I have says 3/8" thread for the YL1.

The puller tool in that book is a slide hammer.

I also happen to have an old Clymer that covers the YL1... says slide hammer too...

If it's as tight on as described, using a slide hammer doesn't sound like the best plan & might break the side out of the case. I'm seriously wondering if the thread doesn't go all the way through the armature & whatever ya screwing in is just getting to the end of the thread & pushing on 'Nothing'. Defies logic that it won't come off. If the proper puller is meant to have a stepped pin going to the end of the internal hole, maybe the armature thread comes to an end as it'll be calculated so the pin bottoms out before the thread ends [guessing of course]. Surprised if it was 3/8 inch size but [if the book says so-ok]. I'd be more thinking if it was before they went 'isometric' fine thread it might be 10x1.5. Not that i 'realy' know what the hell i'm talking about lol, but was was working on them & honda when the thread change came--long time ago.