Topic: How hard is it to split the cases?

[72cafe]

I may break into the case to replace the bearings. I've been told that pulling the cases aprt and putting them back together is a #$%*. How hard is it??? What should I watch/plan for??

[dec505]

This is one of those things that if your asking you shouldn't being doing it. Any shop can press your bearings on for you for around $150 (us).

[72cafe]

I'm not worried about pressing the bearings...More like putting the cases back together.

[bryanj]

WHAT BIKE?

[dec505]

I would just pay the money to have the shop pull the crank out and install the bearings $150 is worth it to me. I wish I could help you out but I have never split a honda case before. I know on  a lot bikes there welded together.

[andy750]

I split the cases last year on my CB750K2 engine (first time for me as well and no they are not welded together). Splitting them is easy enough - just tap gently with a large rubber mallet once ALL the bolts are out -make sure ALL bolts are out -its amazing what you can miss. Putting it back together is tricky and so far I havent started my engine yet to find out if Ive dont it correctly but its re-assembled and waiting to be started so time will tell. However the whole process is very doable. Im no expert and have basic mechanics but with time and patience its not a huge job.

Good luck,
Andy in Boston

[MRieck]

 The most difficult part is getting the middle shift fork in the gear groove when putting the halves together..... it's not that hard.

[bwaller]

It is not a big deal at all. When you're ready to reasemble make sure everything is well cleaned including removing all the old bonding material and don't use anything that will scratch the mating surfaces. I still prefer three bond, but there are good silicone based products also. When you're sure everything is in place, just apply a light layer to both surfaces where the two halves contact. Have all the fasteners clean and lined up ready to reinstall, the torque wrench ready and it clear in you head the torque pattern. Go for it.

[cd811]

the split was easy...reass. took time and patience

[Bodi]

Like others have said, it's not terribly hard.
Make a decent stand so the engine is supported level upside down, wood is fine.
Get a set of oil seals, it's worth replacing them while you have it apart.
On reassembly, test fit it at least once to make sure you can do it properly. I like to test fit all the bolts as well to make sure I have the correct lengths going in the correct holes, and I even drill a piece of plywood with the rough bolt pattern to hold the bolts so they don't get mixed up.
Then coat the mating surfaces with 3-bond type 4 or equivalent semi-hardening sealant, you only have to coat one side of each joint. You want a thin coating so that not too much gets squeezed out, too much inside can form loose lumps that shouldn't be floating around in the oil.
You have about 30 minutes to assemble it once the sealant is on so don't be in a mad rush.
Tighten the bolts in sequence. The bearing bolts are the most important to tighten and torque in sequence, the rest pretty much just hold the cases together so they don't leak but a cosswise sequence is still worthwhile.
Check that the transmission shifts through all the gears before you button up the side cases and reinstall the engine.

[Clyde]

You have not stated which bike, but as I only have experience on 750's I will add my bit related to them.
No 1 rule DO NOT RUSH-Take your time
The hardest part is cleaning everything up ready for reassembly, so do not be afraid of having a go.
The only special tool you need is one to remove the alternator rotor and a rear axle does the job OK.
I always do what Bodi says (well not every time of course) and do a dry run without sealant and make sure everything goes together easily.
My practice is to do a dry run and check every thing then leave for a few days, then check again. If you are sure all parts are in the right places seal it up.
In addition to the crank and countershaft seals I would also replace the cam chain as well as the rollers. You can measure the stretch of the primary chains and if there is more than 68mm I would replace.
EASY
You mentioned bearings-are you referring to the gear box or crankshaft bearings and why?

[mwvachon]

I'm surprised no one mentioned Plasti-guage for the crank? I'm definitely not schooled in lower end assembly - but I'm sure you at least have to check the bearings and the clearances? Anyone have experience in this area? What about torque specs for case bolts?
Just things I wondered about - like I said, have no official training. The only time I've tried this was on a 350 twin. Went together fine - but after all was said and done, I found the crank seemed to drag when turning the motor over. Checked what I could without totally tearing it apart again, but eventually gave up on it. Replaced it with a salvage motor instead.

[cb(r)]

UNLESS YOU ARE DECENT WITH A WRENCH THEN THINK TWICE, OR GET SOMEONE THAT IS TO HELP YOU.
definitley invest in a manual
clean the case really well.  this is to insure you can see all the bolts and not have a hidden one caked in mud or oil
get a gasket kit and oil seal kit prior (or make sure you price them and see if still available)
if need be take pics before and during just in case you forget how to put it back properly
be prepared to purchase crank bearing and yes use plastigage to check.  while you have it apart  it is not the time to cut corners.
also possibly primary drive chain..
take apart and clean everything the gasket material might be hard to scrape off

when reassembly it is best to have a mechanically inclined friend to help
get good assembly lube  and sealant for the case
practice puttig it together without sealant and crank seals just to get a feel for what you are doing. connect rods and other thing can get in the way
then put together and tighten bolts accordingly

I did not do all of this ahead of time and found myself running around buying parts and waiting for them to come in.  also this is for a 550k  not sure on others.