I have several enduros of the above vareous sizes.   While all will not require new cranks,   some will.  Been researching and watching videos, and a single cylinder crank does not seem that hard to do.    Been looking at press prices (new/used) and they vary quite a bit based on size and quality.  

The machine shop I take my work says they have a 50 ton and a 100 ton press, but I imagine they get into some bigger jobs, on bigger bikes (with some being race bikes).   They suggested a 20 ton should do the job for home use, but am wondering if a smaller press might work.

For those of you that have done your own cranks, what do you suggest.   I really do not see myself doing 2, 3, 4, or 6 cylinder cranks.   I might get brave enough to do a 2 cylinder (Motorcycle/snowmobile) but I see myself taking anything larger to the machine shop.

Note,   I play around restoring vintage bikes as a retirement hobby and like to do as much as I can myself.   I do not care to invest in a lot of costly machines,  but a shop press seems fairly reasonably priced for an OK one and seems like it might be nice to have around for other things.

Thanks in advance,   John

It's been a long time ago I rebuilt my 250A crank. I remember the hardest part was pressing the original pin out and I ended up using a large hydraulic press where I worked. 100 ton I think, one of those with a wire safety cage around it and it was over kill but worked. I used what I think / remember was a 5 ton arbor press to press new pin. I spent about an hour to get the the two haves indicated with in the Yamaha specs. I then spent about another four hours trying to see if I could get to indicate perfect, no run out in any direction which turned out to be impossible. It was a fun project and wouldn't hesitate to do another one if needed.
And I made pins that fit close in holes in the two halves to keep them in the ball park when pressing back together.

 Here's my dinosaur. Done many cranks without a problem--well bit fiddly. 20 ton press i found at the scrap metal place--took a trailer load in & saw it sticking out of a bin looking like it needed a home. Cut up the kids old trampoline for the press frame. Going to have to use it again soon on a 360 crank, Which reminds me, i used to use a full face helmet with the visor down if thing were looking dodgy & liable to fly out lol. Nothing stops it, straightened a few fork legs. Looking at the pic trying to work out what the hell i was doing. Was an XT200 rear shock pressing to get the circlip out holding the top bush plate. Looks dangerous now. Top pic should be down below. The XT shock you'd never think it could happen but the mudflap thing that stops mud getting flung up along the shock--in theory anyway--had been inverted i guess for years & it wore through the shock weld until the gas got out. Line across pic is a camera fault but minute crack is about right there. Sorry wondered off the press subject. Yep 20 ton will do it easy.

 

Truing them up can sure be stressful & depending how you do it don't rely on the threaded mag end being true as someone will have belted it for sure. I guess small rollers close to the webs is good & measure as far out as you can get. But i use a center in the lathe & the tail stock opened to get up the taper just before the keyway with gauge close to the wheels. The center the other end always seems undamaged--so far. Initially i line them up with a steel ruler & get them close. Shaft wear can be an issue if the bearing has been spinning on the mag side so far as the dial gauge giving a true indication goes doing it my way. Also pressing them together the damn things go close but then one more jump is too much. I usually get them close then sit a feeler blade of whatever say 12 thou, then press it just under when you think i'll move & then give the press base a smack with the copper hammer & if you do it right it'll creep up little by little --is that a song--showing ya age if ya remember that lol.

This 12 ton press from Harbor Freight worked for me. Also used it to press new bushings into control arms on 2 BMW's.