On the later models at least, the crank seems to be located laterally by clamping it into the right side bearing. That's one reason it "might" be best to pull the crank into the left side bearing during case mating? 

I have installed the crank and bearing into the left case first...  one time the left bearing visibly moved (very slightly) out of the left case when the crank gear nut was tightened.  Other times the crank has been "stiff" turning...  which corrects itself after a smack with a mallet on the end of the crank.  (I hate to do that!) 

You can also end up with a stiff-turning crank overtightening the installer nut during assembly...  or by not tightening it enough and tightening the case screws to bring the cases together the final bit...  In my experience it's fairly easy to knock a crank out of true and you'll likely not notice any significant issue.  Getting crank trued almost perfect and being very careful with pulling the crank into the cases has resulted in a couple of 175 engines that are sewing machine smooth even at high RPM...  so that's what I do, not sure if it matters much or not but seems to.  .  

With the tool to pull the crank in just be sure there's room for the fat part past the taper to go up in the puller tube.
Or might need to use a larger inside diameter short spacer to add between puller & case. Sorry I'm on my vintage iPad & missing stuff if it's been mentioned.

Mark, RT, I have a stiff condition with the dt3 engine I just assembled. What type of mallet did you use to correct the condition. I hit the end of the shaft with a plastic mallet and it seemed to help a little bit but am wondering if I should crack it with a brass mallet. Using a feeler guage to check the inside wall clearences between crank and cases I'm pretty equal, maybe a touch tight on left side, (flywheel). Doesn't seem like it would take much to make it a little bit better. your thought's are appreciated.

Hello I have a YAMAHA RT2 360. I rebuilt the engine 2 years ago. You have some vidéos on internet to install the bearing into a crankase. For example, vidéo: Yamaha 250 MX bearings, seals, paint, plating, crankshaft install:
It is not necessary to have the black tool (on the video) to insert the crankshaft into the crankcase. Simply gently heat the crankcase and bearing with a heat gun. If you prefer to have the part number [TLS077], YAMBITS, England website sells it. I bought it and didn't need to use it. Sorry for my poor English. I am French.
Have a good day !

I use a dead blow mallet (hammer) if needed I’ve had to use it several times 

If you pulled it into the left bearing then assembled the motor & tightened the right side crank nut it'll be trying to pull it across & pulling hard could cause it to feel tight-ish.
Sorry not got time to read up fully on posts at the mo.
It could take a solid hit with a copper hammer which isn't ideal on the mag thread unless you can slide something solid over the thread & up against the step, if there is one, where the thread ends then smack 'that'.
Just thought of another maybe silly idea--fit the flywheel on the tapper with the puller in it. Then smack the puller.
Flywheel should still almost fall off after that.
If all that doesn't neutralise the preload & make it spin free then i'm out of ideas at the mo.
Ok, one more. For a test, undo the crank gear nut & it should free it up--just to prove a point.
Right side probably has a shim & is bolted up agaist it. Left side no shim & a slight gap.

"Note" i stand corrected now i look.
Was thinking early type motor but "77 shows no shim.
Now i look at the early DT1, even that doesnt show one. So i giveup.
Should bolt up tight 'to the right' regardless.
So don't always believe me haha.
images.cmsnl.com/img/partslists/yamaha-d...gyau1064a-8_00a8.gif

RT, my order of ass'y
I first pulled right side,(crank nut th'd), into bearing.
It does have a shim. (right side)
Applied yamabond to both halves.
Then pulled left side in.
Bolted the two halves together.
Then assembled right side drive gears and bits, and tightened crank nut.
 I did not check to see if it was free spinning. .
side note:
Normally I thread a nut onto the shaft I'm gonna crack to save the threads.
Also why I use a brass mallet. Has worked well many times for me.

Hope for a good outcome.
I know i went into a long story about trying to 'not' hit the thread as i've seen them hit that damn hard the thread is bent which makes it an unreliable center when rebuilding the crank & truing it up.
But i guess most people use rollers close to the crank wheels & a dial gauge further out.
I mostly true them in the lathe with a center in the crank gear end because that never gets bent, then i have a chuck the other end that i open up to get onto the start of the taper & avoid using a center in the threaded mag end--as mostly it can't be relied on to be dead center.
Sorry--that was a long story about nothing.

Alright boys I did it. I froze the crank and got the bearing super hot. Dropped it right onto the shaft. Then I froze the whole assembly and heated up the case it dropped right in. Then I started installing the seal and I realize I had no idea which way it went.

Does anyone know if the metal part of the seal faces the crank or not? I have read that spring side goes inside but this has springs on both sides?
Additionally any tips for installing the seals would be welcomed!

If you have the correct seals, they should have "castle turret bumps" on one side.  That side goes in first towards the bearing