Restoration Blog: CB77 No. 1039XX

G-Man · Post by **G-Man** » Thu Jun 20, 2013 1:47 pm

Bob

The head gets very hot around the exhaust ports so it will discolour any kind of silver paint or lacquer. None of these parts was painted at the factory, in contrast to later Hondas. Crankcases were also bare metal. Only the engine side covers were painted.

The Aluminum will not discolour as much as a painted coating at those temps. All of the 50 year-old 305 engines you see will have bare cylinder heads.

With regular heat and a bit of oil or WD40 they just take on that nice patina you see so often.

G

FiremanBob · Post by **FiremanBob** » Thu Jun 20, 2013 4:09 pm

If so, that will help accelerate the re-assembly.

Now I'm cleaning out the combustion chambers. They are very dirty and coked-up, as you can see in the pictures below. What is the easiest way to clean them? I have a glass bead blasting cabinet. I have spent about a half-hour scrubbing one chamber with a brass brush and WD-40, but I estimate that doing it this way will take around 12 hours. The valves are equally bad.

I imagine that the source of all this carbon is connected with the rather glazed cylinders.

I did run a search on the matter but turned up nothing in the first six pages of results.

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LOUD MOUSE · Post by **LOUD MOUSE** » Thu Jun 20, 2013 4:19 pm

I have spare exhaust valves and install them upside down then blast the dome and ports. .............lm

FiremanBob wrote:If so, that will help accelerate the re-assembly.

Now I'm cleaning out the combustion chambers. They are very dirty and coked-up, as you can see in the pictures below. What is the easiest way to clean them? I have a glass bead blasting cabinet. I have spent about a half-hour scrubbing one chamber with a brass brush and WD-40, but I estimate that doing it this way will take around 12 hours. The valves are equally bad.

I imagine that the source of all this carbon is connected with the rather glazed cylinders.

I did run a search on the matter but turned up nothing in the first six pages of results.

[/img]

FiremanBob · Post by **FiremanBob** » Thu Jun 20, 2013 8:10 pm

LM: Thank you. I stuffed rolled paper towels into the valve guides and used the blaster. After 5 minutes, this is the result:

jensey · Post by **jensey** » Fri Jun 21, 2013 1:30 am

Hi Bob,

G-man is correct, no paint on cylinder / head or crankcases. Only paint on the side covers.

jensen

FiremanBob · Post by **FiremanBob** » Fri Jun 21, 2013 10:14 am

Thanks, Jensen. I have committed the heresy of painting the crankcases, but will leave the jugs and head bare.

On the tapper cover question: I see that some slightly later Honda models such as the CB 360 and CB 500 have similar tappet covers, which can be had new for less than USD10 each. Is there a chance that any of these would fit the CB77?

G-Man · Post by **G-Man** » Fri Jun 21, 2013 10:22 am

Bob

I don't know about the tappet covers, worth a try though at those prices? I know that CB160 and CB400F are much smaller.

I had to paint the top crankcase cover of my CB77 as it was corroded so badly. I filled the pits with JB weld and gave it a coat or two of silver plus lacquer. I left the lower part unpainted as it was in much better condition. The number are very close on my SuperHawk so I didn't want to lose that even though the top case was in bad shape. They are within 2. xxx535 and xxx533

G