1972 ls2 100 twin. I have a new arm, seal and gear and I would like to replace.
what type of die or punch do I use to reassemble? A tubular revit die looks like it would work. 
how did you guys do it back in the day? I have posted some pics.

My methods aren't by the book but i just used to spread then with something like tapered punch or center punch just to get it to hold, then think i used small ball hammer hit by a bigger hammer to start it flattening, the just the bigger hammer to finish it off. That probably way over doing it. Done many over the years [but not 'for' years]. Was common on farm bikes as the actuator would bind up on the early Ag bikes running in the case like your LS2. Main thing is to time it on the right twist spline thingy before riveting it on. & of course don't rivet it before putting in the case & grease it plenty. Drill the riveted head off the old one. Sorry i should be smacked for saying that as i'm sure ya onto all the tricks. Love the LS2's & had probably 4 at least over the years. Funny though the roughest [got out of a skip bin] went the best for performance. The tidiest one barely pulled its own weight & i'll try to find a pic of why somewhere on my computer.

Link to the old page.
yamaha-enduros.com/index.php/forums/1972...aust-on-ls2-100-twin 

Thank you so much, I really appreciate the advice. I will grind the end of a cuple old punches. One tapered to squeeze and a larger round one like the end of a small ball peen then use a flat one around the edges to finish and flatten. Mine feels pretty smooth for now and the seal is in one peace. Odometer only reads about 1500miles. So il clean it out and repack with grease for now. If it gets hard to pull il remove and replace it.
Lol nice pipe I bet that did have quiet a loss of power. That's super soaked. I finde that where the right side crank case seal has worn or failed and they start to eat Trans oil. Was that the right side? Kinda looks like it.

 

Not sure now which side that pic is from but both sides were pretty equal for build up. Owner was a customer of ours & each 6 months at wof time [warrant of fitness] i'd note it getting slower but he wouldn't let me 'at it' lol. So when i ended up with it from the next owner [who thought it was slow] i got straight into there. Bike was tidy so didn't want to stuff the chrome except for the weld so used a fork spring with a scratchy end on a reverse slow drill & got it right through the header. Muffler body wasn't bad past where i could reach going in from where i cut it & scratching away. Don't recall ever needing to do a crank seal on the right [or left] on those as weren't hard on them but can see why you asked. Was just many years of non ideal running & the more build up the wider the throttle to get some speed & more oil pump pulled around--all downhill from there. Pic of your bike sometime would be nice. I had red [sort of red] & a blue one--& blue 30 years earlier--& a rust one from the skip bin haha. Talking the clutch actuator & not worth doing in your case but at work with the AG bike yamy 100 single with same principle i used to drill a small hole at an angle & poke some grease in as they suffered badly on the farm with dirt packed in behind even with the seal.

Ya thats a good idea on a greas hole I like that. The pic with it apart some was from 5munths ago and the other one is when I brought it home not long before. It's mutch better mecanicly now. I did a similar technique for my pipes. I removed baffles and old packing then used a brush that kinda looked like a smaller toilet scrubber with a long rod and brass bristles and some gun cleaning brushes and coat hanger rods. I had to repair the rear hub. Someone forgot to put the rubers back in it. Had to tig Weld some cracks In that. It's pretty good cosmeticly for the age. But some where down the line it had a less than knowledgeable owner. Probly the guy I got it from. They Unhooked the auto lube and the right side crank seal was rolled from improper instalation I think. I might have a pic of it. Chain was over tight. Carbs wer clogged tanks a little rusty inside but will clean up good no real piting. Had the blue 2stroke oil in the auto lube tank and atf in the Trans. Por kid I got it from had no idea what he was doin lol. I saved it just in time .

So far
New cork clutch disks aftermarket and oem steals 
Rebuilt with good kits carbs and auto lube pump new seals and all
New base and head gaskets cleaned pistons deglazed cylenders, measured, squish and ring gap all in tolerance cross hatch was ok but I used a 3stone floating deglazing hone so It would not fall in the ports long fine stones only cuple passes each with oil I didn't evan have to take  a hole. 001 off just tighten up the hatch and knock the glaze off,
oem rings with oem set ring gap.
all new seals on the cases besides the actuator one.
new tires tubes rim bands
Wheel bearing in rear front feel good
Deglazed the brake shoes front and rear
Kept stock air cleaner set up but wired foam instead of paper with light oil, hoping to not need to rejet. I think it will be ok.
cleaned repacked pipes new cover seals
Lights tack speedo all work idicators too
running good Ole straight 30 non detergent in autolube and a little klotz in the tank and motion mineral oil 10w 30 for Trans and cork clutch disks.

I worked as a motorcycle technician for almost a decade then went to construction management for the money.  I've built a few cool 2 stroke stand up jetskis and I raced mx as a kid. Just always preferred a 2 smoke they have more soal and take more knowledge to do well with. I could slap together a 4 stroke in my sleep but the art of airflow in a 2stroke takes real thought cause it's all fixed. 

My best friend had a 72 LS2 I always thought it was a good looking ride I wish I had one it’s to bad he died a few years ago so I can remember him when riding it Great job!!!