CB175 - Trouble splitting the case

[1sttimer]

Hey All! I'm new on the forum here, and new to bike building as well. I'm fairly decent mechanically but haven't torn an engine down like this before. I have a 1973 Cb175 that I have stripped to the frame in my garage. I have disassembled the top end and am trying to crack the crankcase to repaint the engine from the ground up. I have removed all bolts from the underside of the engine (including the hidden one under the sump plug), the oil pump, clutch basket...etc.

I have tapped and banged this thing with a rubber mallet at the seam but cant get the seam to budge for the life of me. What am I missing?? I know there isn't a hidden bolt anywhere but I'm wondering if any seals on the side are holding the thing shut.

My other question is about orientation. I've read to have the engine upside down on it's studs with the back of the engine supported. Does this help pieces not fly everywhere when I separate the halves?

Thanks in advance for your help!! I'm ready to get the cleaning done and start painting and assembly!

 

[Scruffy]

If it isn't leaking, tape up any holes and paint it how you have it. Unless the bottom end is making odd (bearing failing) sounds or the transmission is locked up, don't tear it down anymore. Pieces of fuel line over the cylinder studs, wrap and tape a rag around the connecting rods (and pistons if still attached). Nobody but you will know the difference unless you plan to enter it in shows.

You'll get a better paint job from a full tear down and media blasting, but if the engine still works fine, there is no need to mess with its innards.

My 2 cents.

Oh, it's hanging up on alignment dowels. They all do that.

 

[Texasstar]

We didn't split our case but I am pretty sure it is put together with honda bond and you will néed some form of heat to get it apart.

 

[1sttimer]

Thanks guys, I think we have a heat gun laying around somewhere so maybe I'll give that a shot to melt some of the overspray of bonding agent they used to close the thing up in the first place. Since it's so hard to open, I imagine it hasn't been torn apart since production. I definitely want to take the whole thing apart, for learning purposes and also for proper paint.

Any thought to my other question? Do I need to have the engine upside down for the teardown like some suggest?

 

[Scruffy]

Pretty much, that way everything stays where it is supposed to until you physically remove the components. Right side up, stuff can/does fall out. Shouldn't, but it does.

 

[SONICJK]

There is almost always a spot on the cases were one half doesn't overlap the other, a lip if you will.
What I do I place a board against that lip and smack it a few times with a hammer.
Works every time.

Just don't hit it too hard

 

[1sttimer]

Finally got it! I took a heat gun (well I say heat gun, it was more like a high powered hair dryer) and heated up one edge until I could pull the halves apart. The only problem is that it separated violently and the kickstart assembly went flying so now I don't know how to reassemble it...