Topic: Removing Head from Block

[Loudpipe]

How do I separate the head from the block once I've gotten all the bolts/nuts off the motor?  It seems like it's still pretty well stuck on there.

[paulages]

make sure you have the 5 screws out that hold the two together- four underneath the little round seals under the cam towers, and one above the cam chain tensioner. i use a mallet and a drift of some kind, and knock around a little bit on anything but the fins. you can tap upward on the exhaust spigots, or a little on the intakes. don't go crazy on either, 'cause they can get damaged easily. if it still doesn't break, take a razor blade and cut into the gasket at the corners. you want to be careful not to #$%* up the mating surfaces, but you can safely wedge a sharp screwdriver (or a scraper of some sort... just make sure it's not blount)  in a few places and lightly tap. don't go crazy with this or you will scratch it up.

be patient- it wiill come off. just don't tap the fins.

[Loudpipe]

I got the head off, but since I'm just doing a headjob, new valve guides, seals, all that, is it necessary to remove the block (the middle section) from the lower engine casing? I can't figure out how to get the tensioner and guide out (or back in later) without doing this.

[Patrick]

You have to remove the block to remove the chain tensioner. Also, if you had to pound the head off, you likely compromised the gasket under the block. If it were mine I would go ahead and remove the block too.

Patrick

[Loudpipe]

Probably a good idea.  The tensioner is a little bit eaten up anyway.  How does the block come off?  Just kind of tap it off like the head, or do pistons, studs, etc. have to come out first?

[jonbuoy]

I was breaking down a knackered CB750 motor the other day for spares - the block was already shot so I used a rubber faced mallet and beat the S$#t of it round all the faces of the block - on the fins - no damage to fins and didn't munt any of the gasket surfaces.  I'll be using this technique on my next proper rebuild.

[paulages]

I was breaking down a knackered CB750 motor the other day for spares - the block was already shot so I used a rubber faced mallet and beat the S$#t of it round all the faces of the block - on the fins - no damage to fins and didn't munt any of the gasket surfaces.  I'll be using this technique on my next proper rebuild.

you got lucky with the fins. they bend very easily and don't bend back without breaking.