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1966 CB77 Restoration Project

Want to keep a Restoration Log? Post it here! You can include photos. Suggested format: One Restoration per Thread; then keep adding your updates to the same thread...
LOUD MOUSE
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Post by LOUD MOUSE » Tue Jan 30, 2018 1:39 pm

The cases for these 250/305 HONDA engines were not line bored and you CAN use any top to any bottom as the casting/machine work is that good. ......................lm

Geoff Hastings wrote:I can't see why aluminium brazing won't work or even take the case to a competent aluminium welder, I've had magnesium cases welded successfully after so called specialists told me it couldn't be done. Changing just the top half of the casing may be a no go as usually cases are bolted together and then line bored making them a pair. If you do end up getting it welded you should bolt the fully stripped cases together to help avoid distorting one half of the casing.

Geoff Hastings
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Post by Geoff Hastings » Tue Jan 30, 2018 2:58 pm

That's good to know, cheers LM.

LOUD MOUSE
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Post by LOUD MOUSE » Tue Jan 30, 2018 3:17 pm

Welcome. .....................lm
Geoff Hastings wrote:That's good to know, cheers LM.

jkv357
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Post by jkv357 » Tue Jan 30, 2018 9:15 pm

Seadog wrote:
I finished the disassembly yesterday, having decided to strip the bike completely and remove the bare frame from the engine. It all worked very well to that point. My luck soon ended. I have a motor stand that I was able to attach and I lifted the motor with stand to a Workmate so that I could dismantle the head. Unfortunately, my short height, the height of the Workmate and the height of the motor stand worked against me. I was unable to do it and down we went. The top portion of the head took a beating and I ended up with 3 stitches in my face.
Sorry to hear that. Thankfully it wasn't worse.

Heal up!

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G-Man
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Post by G-Man » Thu Feb 01, 2018 3:00 pm

Seadog

Sorry to see that you hurt yourself. I've been thinking of building myself myself an 'engine crane' as I had a similar accident last year.

G
Seadog wrote:Thanks, G.

I finished the disassembly yesterday, having decided to strip the bike completely and remove the bare frame from the engine. It all worked very well to that point. My luck soon ended. I have a motor stand that I was able to attach and I lifted the motor with stand to a Workmate so that I could dismantle the head. Unfortunately, my short height, the height of the Workmate and the height of the motor stand worked against me. I was unable to do it and down we went. The top portion of the head took a beating and I ended up with 3 stitches in my face.

Before I went on my emergency room excursion, I was finally able to get the motor, with stand, onto the Workmate and remove the top of the head to see the piston tops. the left piston was a gunky mess. Later, I cleaned it up, removed the cam chain and gave both stuck pistons a beating with a block of wood and a dead blow mallet. No luck whatsoever freeing them. They've now been soaking in BP Blaster overnight and I will give the mallet another try a bit later.

The remainder of the day today will be dedicated to organizing parts - separating the paintable bits and boxing up the rest. I think I might also do some searching for another top head....

No photos because the site doesn't seem to be accepting them today and tells me that I'm trying to upload and empty file.
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160
'66 Matchless 350 '67 CL77
'67 S90 '77 CB400F

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Seadog
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Post by Seadog » Thu Feb 01, 2018 4:39 pm

Thank you both, Geoff & LM for info about brazing/welding and cases. I haven't given the case problem much thought as I've been trying to free those stuck pistons, but I'll have to get to it sooner or later. Now I have a broken head fin to add to the pot.

Thanks to jkv357 and G-Man for your kind words. I'm healing up. The stitches came out today, so my rugged good looks are preserved. The inside of my mouth is a bit sore and swollen, but healing quickly.

I spent some hours today working on the motor. I split the cases and stripped out everything. In the gunk around the oil pump I found the kick start pawl, spring and cap and an as yet unidentified piece of aluminum. It almost looks like a piece of fin. I'll figure out what it was at some point. The transmission gears look good at first glance, except for first gear on the start spindle. The teeth on the starter side are very worn and it should be replaced.

I made up a frame of landscape timbers to support and hold the top crankcase and cylinders and tried once again to free the pistons with a 4 lb. sledge hammer and blocks of wood. No movement at all of the pistons or crankshaft. I'm just splintering wood. I'm thinking a piece of pipe might be required to replace the wooden blocks. But I'm also wondering if it's more than stuck pistons.

When I was removing the shift drum, I found the shift forks to be solidly stuck, even though neither they nor the shift drum were rusted. They were coated with dried oily mess that stuck like glue. I applied PB Blaster, tapped them lightly with a small piece of wood and they slowly freed up. The same dried oily mess is all over the crankshaft weights and piston rod ends and I'm wondering if it's part of the problem. In case it is, I've flipped the case over and liberally applied PB to the sides of the rod ends. If I could just get a little movement they'd be free.

More work on the mess tomorrow. Any thoughts on freeing those pistons would be appreciated. I really don't want to get into cutting the sleeves or drilling the tops of the pistons if I don't have to.

rustywrench
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stuck engines

Post by rustywrench » Thu Feb 01, 2018 5:30 pm

It is hard to comprehend how strong the rust scale can be but it is. I once bought six stuck engines and began the laborious task of tearing them down. In some cases they came apart quite easily. The extreme case was one that just would not budge. I was determined to separate the parts so I suspended the whole eng/trans above the floor by a chain wrapped around the block. I have a 1 3/8 socket that fits in the cylinders. Next came the 6 lb maul to drive the piston loose. The rust was so stubborn that the top flange broke off and I drove the sleeve out of the block on both holes. On yet another the next better alternative was the drill. I haven't tried it but a hole in the top and a saws-all out to steel would relieve the pressure enough to get movement. Likely as not you will probably need to re sleeve any way you go. Just some food for thought. Good luck Dog, Rusty

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