Topic: Silly question - How to get the head off?

[kaysystems]

Last winter the head was off my CB750 K0 to put new valves & guides in.

Now I'm seeing an oil leak on the barrel and it runs a bit rough (not carbs or ignition - clean like new carbs & spot on ignition). I figured I'd take a look inside to check the valve sealing.
I took ALL the head nuts & bolts off, but that super sticky Honda head gasket wont let the head come off. The bas gasket is loose, as I have oil leaking now, but can't get the head to separate from the barrel.

Please.....what's the trick?

David

[RRRToolSolutions]

Do you have the 4 6mm screws/bolts removed from under the cam towers? Those 6 rubber sealing washers under the towers hide/cover 4 6mm bolts with phillips heads.

Regards,
Gordon

[750goes]

has the cam chain been removed/loosened - a reall dumb question

[kaysystems]

Yep

Every bolt is off. The Cylinder is loose at the crankcase. It moves fine there. Just the head gasket is really stuck. I used a genuine Honda one that was covered in brown sticky stuff - presumably to stop oil leaks.

David

[Gordon]

Put the spark plugs back in their holes and turn the engine over a few times with the kickstart lever.  If you do in fact have all the nuts/bolts removed, the pressure will pop the gasket loose. 

[kaysystems]

Put the spark plugs back in their holes and turn the engine over a few times with the kickstart lever.  If you do in fact have all the nuts/bolts removed, the pressure will pop the gasket loose. 

Thanks

but since the cylinder base gasket is loose, wont it just lift it from the base?

David

[Jonesy]

The newer Honda head gaskets have cutouts that correspond to slots milled into the head and cylinder. These were pry slots, one on each end of the cylinder. (Not sure if the K0 had these or not).

[kettlesd]

If yo do decide to pry - be sure to use a wide wrecking bar instead of a big screwdriver. It disperses the stres better and less liekly ot mar metal or slip and break a cooling fin.

[kaysystems]

The newer Honda head gaskets have cutouts that correspond to slots milled into the head and cylinder. These were pry slots, one on each end of the cylinder. (Not sure if the K0 had these or not).

 

Just looked for them. The new one I bought has, but the one on the engine has none. I'm thinking solvent.

David

[Tim.]

Well, at this point some might suggest you need to replace the base gasket seeing as you've lifted the cylinders, so you could always just pull the head/cylinder right off and work on taking them apart.

That being said, wouldn't a leakdown test have been able to tell you if your valves were sealing well?

[seaweb11]

Tap with a rubber mallet....or
Use a piece of wood and place against head at different points and tap wood with a hammer...gently

[MRieck]

 It is probably hung up on the dowels located towards the front.

[kaysystems]

Well, at this point some might suggest you need to replace the base gasket seeing as you've lifted the cylinders, so you could always just pull the head/cylinder right off and work on taking them apart.

That being said, wouldn't a leakdown test have been able to tell you if your valves were sealing well?

I really don't think thy are leaking, after doing the leakdown. It's something else, but since I have an oil leak showing on the front of the barrel, the head is coming off to find it

David

[kaysystems]

It is probably hung up on the dowels located towards the front.

I just can't get any movement. I'm sure it that brown sticky stuff that was all over the gasket (honda OEM)

David

[mwohlenhaus]

I just tore my motor down, and it was more difficult that just pulling it off.  I just started tapping the head with a rubber mallet all around, and eventually it let go.  I was lookin for pry points on my 76K and did not see any, and I know better than to stick a screwdriver in there to pry it apart.  any way once i got it started it came right off.

[kaysystems]

Finally got the head off. I tried the soft mallet too. I eventually found the pry slots in the gasket (my eyes are getting too old for this stuff) and after a lot of prying the gasket let go.

The attached picture shows a minor oil leak problem, despite all that brown sticky stuff

[bryanj]

Cant tell where leak was from the picture BUT the bolt hole in the gasket centr top looks like there is no hole in the head and very close to a gallery, was it deffinately the right gasket?

[kaysystems]

Cant tell where leak was from the picture BUT the bolt hole in the gasket centr top looks like there is no hole in the head and very close to a gallery, was it deffinately the right gasket?

Defenitely the right gasket. It's the only one they sell for a K0. Surprisingly it didn't leak there, but ran under the gasket from the cam chain tunnel and down the small bolt hole to the side of the chain. it then dripped onto the 3rd fin down on the cylinder & made a mess.  The oil also looks like it comes from the head drains. The K0 have NO seals on any studs except the oil feed ones.
This suggests too that the cylinder barrel may not be flat (head was ground flat 5000 miles ago). I'll check this out tonight.
HondaMan has stated that the cylinders will settle after the first few thousand miles & should be rebored to re-align the bores. This may have caused other problems too.

David

[bryanj]

OK Having looked in my 74 parts book there is only one gasket listed, those holes at the side of the chain tunnel are where 2 of the 4 bolts that are covered by the rubber "pucks" under the cam towers are.
Assuming they were in there and torqued up there is one possibilty i have come accross before.

Check where they screw into the cylinder block and sometimes you can see where the thread area has "Lifted" up from the main gasket area--as if the thread was going to pull out.
What we used to do was take a large drill bit (about 1/2"--3/4") and turn it in the hole by hand to put a small chamfer on the hole then make sure the barrel was flat.

For oil to creep there there has to be a lack of clamping force and the only reasons i can think of for that are :-

Bolts not there
Bolts too long,  "stretching" or holes gunked up
Threads pulling or raised (See above)
Damaged gasket surface on head or block

I am not suggesting you have done it wrong or left bits out, just trying to think of why it should leak.
Regards Bryan

[ofreen]

Glad to see you got the head off OK. 

I didn't see this post earlier, so this suggestion is a little late, but somebody might be able to use it.  If you have a leakdown tester, you can screw the fitting into a sparkplug hole and use compressed air to pop the head loose.  It will work a lot of times.  If you don't have a fitting, you can make one by busting the porcelain guts out of a spark plug and welding on a pipe nipple.

[Hockers Choppers]

Damn good idea ofreen!!!
Thanks for the tip!

[kaysystems]

OK Having looked in my 74 parts book there is only one gasket listed, those holes at the side of the chain tunnel are where 2 of the 4 bolts that are covered by the rubber "pucks" under the cam towers are.
Assuming they were in there and torqued up there is one possibilty i have come accross before.

Check where they screw into the cylinder block and sometimes you can see where the thread area has "Lifted" up from the main gasket area--as if the thread was going to pull out.
What we used to do was take a large drill bit (about 1/2"--3/4") and turn it in the hole by hand to put a small chamfer on the hole then make sure the barrel was flat.

For oil to creep there there has to be a lack of clamping force and the only reasons i can think of for that are :-

Bolts not there
Bolts too long,  "stretching" or holes gunked up
Threads pulling or raised (See above)
Damaged gasket surface on head or block

I am not suggesting you have done it wrong or left bits out, just trying to think of why it should leak.
Regards Bryan

Thanks Bryan. The head was skimmed, so I assume it isn't that, but I will check & maybe relieve around the threads a bit.

David