Topic: Cylinder head removal CB750

[gnarlycharlie4u]

Danger Will Robinson!

Yes there are 4 in a row under the #1,3,4,and 6 biscuits.

These should be removed BEFORE removing the head nuts. Once the head nuts are removed the swell of the gasket and the cylinder head serve to increase the torque on those dudes tremendously. To the point where you can barely, if even, get them out. You may want to consider reinstalling the cyl/head assy, onto its studs, tighten the nuts back down, then remove the 4 under the bungs.  This can be done easily with the pistons off.

If you have a long Phillips bit, you could use an impact driver on them.

Impact driver works but it's hard to find one that long.
I still prefer using a deep socket. It's made short work of 3 motors so far.

[john campling]

Here's what I did
Took the head and barrels off together as it quickly became obvious it was not going to give up without a fight.
Cut some 60mm mdf disks which slotted in the bores like mdf pistons, just to protect the top of the combustion chamber.
Planed a bit of wood to fit in the bore and hit it with a hammer. The problem was getting enough grip to stop it moving so I ratchet strapped it to the bench so it was resting on the wood and the carb inlets. I thought this might be enough to split it , not quite. So I gave a few taps with a hammer on the wood in the bore and off it popped.

[Romhog]

good one! never ever thought of putting an adjustable wrench on my wonder bar! great torque with that !  thanks for sharing!

Figured I'd post what worked for me:
I used a wonder bar in between the cylinder and head and twisted it with an adjustable wrench rather than prying it up and down. After about 2.5 hours trying other methods, I was shocked how easy this worked (though I'm sure the dead blow probably loosened it a little!)

[AgPete139]

These should be removed BEFORE removing the head nuts. Once the head nuts are removed the swell of the gasket and the cylinder head serve to increase the torque on those dudes tremendously. To the point where you can barely, if even, get them out. You may want to consider reinstalling the cyl/head assy, onto its studs, tighten the nuts back down, then remove the 4 under the bungs.  This can be done easily with the pistons off.

If you have a long Phillips bit, you could use an impact driver on them.

Since I'm not the sole one reviving this thread, I will shine some light as well.

My #3 Phillips screwdriver started to strip the heads of the 4 bolts underneath the "condom" bungs. Like McRider stated, take these off FIRST before the cam nuts. (I didn't, but I learned now.)

I happened to have a cheap-o socket set from years ago, and the cheaper sets have thin walls. If you can find a thin-walled 10mm socket with an extension, do this. I practically stripped the head of one Phillips bolt.

Procedure:

• Let soak with PB Blaster or penetrating oil.
• Phillips screwdriver into bolt. Give a few solid (NOT Hulk strength) taps (to shock the threads) with a metal hammer.
• Put thin-walled socket on bolt. Use a large extension on your socket wrench. (or breaker bar)
• Remove bolts. Continue to turn, even though they feel like they will not give. They will.

NOW, as far as remove the cylinders (jugs) and the heads, I am currently at a loss. The gasket material is still soaking since yesterday, and I will try later today with a putty knife. Minor tapping with a thin wooden wedge will also be used.


Rubber Mallet Usage:
After reading so many other people's anecdotes, I attempted to hit it with a medium-soft polyurethane mallet.

BEWARE: If you do this, ONLY strike the top head. Hit it directly, in a flat manner. You can break the fins of the head. MORE LIKELY, is that you will break off pieces of the brittle cylinder fins instead. They don't bend, they only break. These are a lot thinner, and you can accidentally bump them while trying to remove the head. I found out the hard way. I will JB Weld it back on though and black paint over the entire part.



Good luck to future readers.

[JerrodR]

Replacing a head gasket, and am running into the same issue. I'm considering taking a propane torch and heating along the gasket line to hopefully melt some of the glue, and loosen things up a bit..

[MRieck]

Replacing a head gasket, and am running into the same issue. I'm considering taking a propane torch and heating along the gasket line to hopefully melt some of the glue, and loosen things up a bit..

Sometimes only bead blasting or vapor blasting will clean the surface.

[HondaMan]

Replacing a head gasket, and am running into the same issue. I'm considering taking a propane torch and heating along the gasket line to hopefully melt some of the glue, and loosen things up a bit..

In the old days (before I had a wife who protects her oven from people like me) I would put the stuck-together top ends in the oven at 200-250 degrees for about 20 minutes. This softens the sealant in the old head gaskets. Then I'd take them out (with winter gloves!) and start the prying, they usually separated right away.

Now I have to leave them out in the Colorado sun, which only gets them up to about 120 degrees on a hot summer's day...