Bottom end re-assembly???

[OldTimer]

Got a new Hot Rods crank assembly, new bearings, and seals. Now it's time to put it all back together and I'm worried about pressing the case halves back together without what they call a crankshaft jig to maintain the exact spacing between the crank halves.
I'm thinking about using the ole hot/cold method of heating the case halves and freezing the crank before pressing them together, however the seals on the KX65 go in from the inside and therefore must be inserted before the bearings. I've also heard that KX65's have an unusually tight press fit between main bearings and crankshaft ends.
Sooo... the seals are obviously designed to withstand heat during normal operation and I guess I could heat the case to around 200 degrees F or so?, but is that hot enough? Could I go hotter? Could I get by with less heat? Should I just go buy the spacing tool?
Any insight from those who've done this would help to ease my suffering... :bang:

 

[2strokerfun]

The bike I just put together has one of the seals inside the bearings. The left one is outside the bearing. I freeze my bearings before putting them in the case. And, like you've heard, many people them freeze the crank and heat the cases before putting the crank in.
Well, I don't. I'm like you and afraid to subject my seal to the heat. I did freeze my crank, but then, put it in and simply tapped the cases with rubber mallet until I could get the case bolts (screws) to catch. Then, I went around and slowly tightened them in the correct order.
Works like a charm every time, but I'm sure there are experts on your bike that have the perfect answer you need.

 

[84cr125]

hold on ill get my manual, quote on my manual "the crankcase must be heated in an oven to about 100 deg C(212 Deg F)" The bvest way to do is flick a bit of water on the cases and if it evapourates immediately then its good. And these specs are from a cr125, which runs a little hotter than yours, so your probably good with 200. Just watch out when you start hitting the cases the bearings that are already installed dont fall out.

 

[whenfoxforks-ruled]

If you do not want to buy the tool then use a c-clamp,leave the hammers for body work and carpentry! I would not heat that case up more than the operating temperature.

 

[2strokerfun]

In all honesty, I'm probably more afraid of my wife than I actually am of hurting the seals by putting the cases in the oven. But I had some German Solo 220cc engines for an ultralight once that you absolutely could not assemble without using an oven. That was before I was married. Sigh........

 

[whenfoxforks-ruled]

Still is not as good as the hot wash cycle of the dish washer,it removes microscopic metal particles! I have listened about that slight miscalculation for a while now,25 YEARS! Get your own,this one is mine The oven is not bad or sitting in the sun,but a guy with a 2000 degree torch and a hammer,well I hope you get the picture,ever seen residual oil catch fire?

 

[OldTimer]

We've got an oven in the kitchen at work, so I've got two choices...
I can either do it at work while the boss isn't around, or I can do it at home while the uh... boss isn't around.

 

[mxdj666]

just freeze the bearings use a block of wood and gently tap them in making sure that they are nice and square going in , i've done a ton this way never had a come back