I have an opportunity to have the guy honing my cylinder/pressing rod pin, to press the main bearings on the crankshaft.  Is this a good idea or not? 
The plan BEFORE was to freeze the bearings, then heat case.  Would it be easier to just heat the case w/the bearings already pressed on?



 

All manuals suggest bearings in the case and every rebuild I’ve read or watched for numerous engines, also install in the case too.
A motorcycle mechanics tool box will always contain a crank puller, it seems the only way but I’m no motorcycle mechanic........

Don't claim to be a motorcycle mechanic, but I did stay in a Motel 6 once and have a crank install tool.  I think I'll be putting the bearings in the cases first. Pulling the bearing in to a case would seem physically more difficult than pulling a bearing on to a crankshaft.    


 

Trouble with that idea is that crank is bolted hard to the right side bearing & there's always a minute, very small washer thickness gap to the left bearing as left relies on a tight fit where right is a zero clearance push fit & bolt up. If you have a crank puller you could assemble the trans & crank into the right side & nip the crank nut up. Then pull the left case onto the crank--having bearing in the case first as you said--just have to be a bit careful getting the trans shafts & selector shaft etc to find their place in the left case as you go. On the other hand, if you had the crank in the left case before assembly then the crank will need a gentle BANG on the mag end after tightening the crank nut on the other end to centralize it or free if from pulling sideways on the left bearing. Some parts lists show a washer between left bearing & crank. That's wrong but will have one on the right side which is as i said bolted up solid to the bearing. I've assembled them both ways depending on my mood or if i'm spacing up my dodgy gears & shafts so just carry on from which side i'm in at the time. Talking earlier 360 generation motor in my case but same deal really.

I was taught to install the bearings into the case halves by heating the case and installing a frozen bearing into the bore, which works quite well really. I will install the crank assembly into the right side first, and snug up the primary drive gear/nut. Then install the right side into the left, which will usually start to 'bind up' at some point, and finish up by using a puller from the left side. Don't forget the case sealant.
Most of us have our own personal ways of doing these tasks, and I am sure that you will develop your own. Take your time, pay attention to the details, don't force things.

You got this.