Rehabbing the head

FiremanBob · Post by **FiremanBob** » Sun Oct 04, 2015 9:19 am

My '64 CB77 is back on the bench after years in boxes as we moved around the country. Now we are in Virginia.

It looks like this engine was terribly abused in its 13K mile life - run low on oil, overheated. I think I have taken on the wrong bike for a first restoration project. But I soldier on...

Aside from two broken valve springs (will replace all 8) I have these difficult issues:

1. Inside of the head - all interior surfaces - is covered in baked-on oil that is very hard to remove with solvents and a brash brush. Some of the areas, around the valve guides, are just too tight to get the brush into. Is there a way I can soak the head in something that would make it clean without many hours of brushing? I have a HF parts cleaning tank that I could fill up if I know the right stuff to use.

2. The copper exhaust header gaskets seem to be fused to the head. They have been soaked in PB Blaster for a couple of days but aren't moving. How can I remove them?

Thanks.

48lesco · Post by **48lesco** » Sun Oct 04, 2015 11:19 am

FB - Don't despair. Those heads are all over ebay for not that much if it comes to that. On the copper rings, drive a small screwdriver gingerly between the O.D. of the copper and the I.D. of the exhaust port. Pry it out. You will destroy them, but they are available from Honda and cheap. As for the head, without seeing it it's hard to say. I would probably suggest getting it as clean as you can with solvent then bead blasting. I wouldn't worry too much about surfaces that aren't sealing, mating, machined, etc. in other words cast surfaces. They could be a funny color and only you would know. You can't buy the stuff that removes that in any kind of quantity anymore. But you could try gumout spray. I'd just bead blast the areas you're worried about then flush it with water for a long time...
-48

FiremanBob · Post by **FiremanBob** » Sun Oct 04, 2015 12:38 pm

Thanks. I already have the header gaskets in my gasket kit. I just don't want to damage the aluminum.

The combustion chambers, ports oil galleries and gasket mating surfaces all seem to be ok, so I don't believe it will be necessary to replace the head. I just want it to be properly clean while it's apart - good for cooling.

I read somewhere that I can boil it in a large pot with a few dishwasher detergent tablets mixed in. I'm going to give that a try.

Tim Allman · Post by **Tim Allman** » Sun Oct 04, 2015 12:53 pm

If there's an engine machine shop nearby you could ask them to run it through their parts cleaner. They almost certainly have one and the results can be spectacular.

G-Man · Post by **G-Man** » Sun Oct 04, 2015 1:20 pm

Bob

It's geat to do as much as you can but this is one of thoe occasions where you might just take it to someone who does bead or aqua (beads and water) blasting. The rusults are fabulous and it just saves tons of time.

I had my 1961 CB72 engine aqua-blasted.

It looked pretty horrible to begin with......

G

FiremanBob wrote:Thanks. I already have the header gaskets in my gasket kit. I just don't want to damage the aluminum.

The combustion chambers, ports oil galleries and gasket mating surfaces all seem to be ok, so I don't believe it will be necessary to replace the head. I just want it to be properly clean while it's apart - good for cooling.

I read somewhere that I can boil it in a large pot with a few dishwasher detergent tablets mixed in. I'm going to give that a try.

FiremanBob · Post by **FiremanBob** » Sun Oct 04, 2015 1:32 pm

I have a bead blasting cabinet from HF and a 50 lb box of glass beads. Can I blast the combustion chambers and everything without damaging them?

G-Man · Post by **G-Man** » Sun Oct 04, 2015 2:00 pm

You won't hurt the combustion chambers as they are cast iron.

G