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A Bomber barn find

Success! The combo of the courage to grind a bit more and using a punch to drive the pins back and off came the link. So I went to it on the new chain and that one went much easier because I wasn't so ignorant of how it works. Thanks to everyone.

I draped the chain over the sprocket on the crank and sealed and then put the two pieces together. How do I know how much cam chain to leave free on each side. I know the assembly ends with putting in the master link at the intake camshaft sprocket, so I left a lot more toward the front of the engine, but that's just a guess. Is there a system? I could put on the magneto rotor temporarily and set the crankshaft at LT, rotate it 90 degrees counterclockwise and if I knew how long the chain should be on one side before I put on the cylinders it would be helpful.
 
wentwest said:
...so I left a lot more toward the front of the engine, but that's just a guess.
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You have the right idea, but you really don't need to worry too much about it because you can actually slip a little bit of chain around the crankshaft sprocket once you start putting the top end on.
wentwest said:
Is there a system?
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LOL, only the one you devise after working on them for a while. I never got to go to Honda school so I don't know exactly what they would have taught about it, but as long as you can get the chain lengths appropriate for intake and exhaust side it really doesn't matter.

If you can't easily get the chain to slip around once the head is in place (with the exhaust cam already rotated into the correct position for the timing mark), then just lift the head up half an inch, slip a screwdriver or thin block of wood between the head and cylinders (carefully, and on the left side so you don't disturb the o-rings on the right) and then you can rotate the crankshaft a little without worry of bumping a slightly open exhaust valve to finagle the chain where you need it.
 
OK. On to step 173(b)(2) of the never ending saga of the K0. I have to wait for a few part deliveries, then the head goes on. Meanwhile, there's a K0 starter that could use a bit of attention.
 
ballbearian said:
In all my bicycle shop years, I never encountered a bush chain and was unaware of this. Thank you Jensen.
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In the 80's and 90's Izumi used to make a sintered metal final drive chain, 530, 5/8"x3/8" pretty much identical to the 'bush' type. I liked them, lasted a very long time particularly if you flipped them to use the 'top' as with sintered metal bushing they didn't rotate
I've never seen or heard of one in bicycle size though.
ballbearian said:
Is a press-on the same as a spring clip type?
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Press fit is for the side plate, it can be rivet or 'fish clip'
 
Starter rehabbed. It was very dirty at the brushes and the positive brush spring had rusted through and was broken. It took quite a bit of solvent and wiggling to get the brush out of the holder, so I took a lot of time cleaning inside it and the negative one as well, of course. The brushes were fine, nearly full size. Relubed things, new springs, reassembled and tested it and, zingggg - it worked just fine.

Then I turned to the standard pistons and cylinders. One piston was quite scarred on its sides although the bore was OK. I honed both bores, replaced the rings on the better piston, got a new piston and new rings for the other bore and put the pistons into the cylinders. I rubbed some assembly lube onto the bores, just a thin coat all over. They are pretty tight feeling. I have to push then hard to slide them up and down in the bores. Is that how it usually feels? The only times I've had engines this far apart it was for other issues and I reused the old rings so the pistons moved pretty easily.

Before I put everything together I did check the end gaps of the rings and they were within spec. They went on to the piston without much drama and moved around in the grooves easily.
 
LongDistanceRider said:
I will only use oil on cylinder walls, not sure about assembly lube but it sounds wrong to me.
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Assembly lube generally has a lot of Molybdenum which will be great for long term storage , not so great to actually bed in rings or cylinder.
Very good chance rings will glaze and you'll have a lot of blow-by
Unless I'm storing cylinders I don't oil them at all.
Only oil piston skirts below rings.
If pistons are already on rods, I squirt oil around big ends, build motor with only the oil on piston skirts then get it in frame and started soon as possible.
Oil flung out from big ends at 2,000 rpm provides plenty of splash lube as soon as engine starts plus guarantee's great ring seal. (I do hone cylinders with 400 grit stones though to get best surface)
It's also better for small ends, rocker pads and anything else that needs 'splash lube'
Maybe wash cylinders in diesel, it will prevent any rust and burns off quick.
 
Wiped out the cylinders with a cotton rag, then smeared a thin coat of motor oil on the cylinders. Now the pistons slide a lot more smoothly and it feels much better. I'll keep these notes in mind as the next step is to try to set the cylinders and pistons over the con rods and put in the pins and clips from the sides. This way it was pretty simple to get the rings compressed and the pistons into the cylinders. I think there's enough clearance to do it this way, but if not it's pretty straight forward to try it the other way - pistons on con rods first, then set the cylinders over the pistons and rings.
 
So the month of March wasn't my best. I tried leaving the pistons in the bores and dropping the whole thing (gently) down so I could run the wrist pins through the pistons and the small end of the con rods. Not real easy, but I messed with everything and got them in place and secured, but in the course of doing that the pistons backed out of the cylinders a little bit, so the lowest ring of the 3 part oil ring, both pistons, came clear. I thought I was able to press those rings together enough so that it went inside the taper area and then back into the bore. But I guess not, because things got real tight real quick and I could not pull the bores back off the pistons. It was clear to me that those rings had gotten jammed somehow and I wasn't Mr. Happy anymore. I spent the rest of March wondering how to get things apart and finally decided a big puller with its legs hooked under the cylinder and the screw against the top of a piston (with something like a small block of wood to protect the piston top) would push without doing too much damage.

A trip to O'Reilly Auto parts to borrow a 6" puller, some bumbling around and (sound the trumpets!) things came apart. The rings were bent and jammed. I had 2 more so the bent ones were removed and ditched, the new ones put in, and now I'm trying to decide whether to try the same system again or leave the pistons on the con rods and carefully push the cylinders over them. There's just so little room to work with a ring compressor. How do people do this?
 
It's not easy Bob, and with stock bore (or just a repair oversize) it's about as easy as it ever is. Some use large hose clamps to help, or buy a pair of Honda ring compressors (Mike Nixon might still have a set).
 
ancientdad said:
It's not easy Bob, and with stock bore (or just a repair oversize) it's about as easy as it ever is. Some use large hose clamps to help, or buy a pair of Honda ring compressors (Mike Nixon might still have a set).
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Seems reasonable. I have some big hose clamps, I'll try that. A regular ring compressor is too tall. Thanks for the speedy reply. I'm sorry I can't send you some Bay Area air conditioning - 60 and sunny all day.
 
So, I got back on to the engine and compressed the rings with hose clamps, put the cylinders back over them, nudged and shoved and tapped the cylinders over the rings and down far enough to take the hose clamps off. Then I started to slowly bring the cylinders down, pulled the timing chain up and through, and started to wonder why there was so much friction between the piston rings and the cylinder walls. Should I be able to push the cylinders all the way down with my hands? I couldn't do that. With a block of wood against the top of the cylinders (between the bolts) I could gently hammer them down to the base with my trusty rubber mallet, but I could not turn the crankshaft at all by hand. There was plenty of motor oil in the cylinders. Should they really be this tight? I pulled them off by hand with someone else holding the block down.

So are they too tight? I checked the ring gaps inside the cylinders and they seemed OK. I got them from 4into1 and they are sold as standard rings, no overbore. The pistons are also standard and slide through the cylinders easily without rings.
 
Does sound unusual for cylinders that were not bored. What ends gaps did you find? Within spec? Are they Honda pistons with ART on the wristpin area?
 
ancientdad said:
Does sound unusual for cylinders that were not bored. What ends gaps did you find? Within spec? Are they Honda pistons with ART on the wristpin area?
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The gaps were OK. I don't remember what they were, but they were within spec with the FSM when I checked them. The friction surfaces of the rings were black, which was a surprise because I expected shiny steel there. One piston is marked with the letters AP, nothing else. The other is marked Honda 292 and the number 5. I'm not expecting these to be K0 parts, and 292 indicates early K bikes. They both measured just a bit under 70mm, maybe 69.4 or 5 with my lousy gauge, 69.3 with the Harbor Freight electronic gauge.
 
We got the cylinders back on (new lower gasket, new rubber rings around the base of the cylinder sleeves) and then put the head on (new head gasket, new rubber sleeves around the 2 right side head bolts), fished the cam chain through and secured it so it can't slide back in. I just spun a couple of head nuts on to keep things together, lots more to do. We got a lot done today and I'm hoping it was done right. My neighbor helped all afternoon. I'm proud of us two old guys (78 and 80), and I'm tired. Thanks for the guidance today - it got us to keep trying.
 
wentwest said:
We got a lot done today and I'm hoping it was done right. My neighbor helped all afternoon. I'm proud of us two old guys (78 and 80), and I'm tired.
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I hope it turns out well. It's nice to have a neighbor that will lend a couple of hands for a job like this.

I've noticed the tightness of new rings before also. I wonder if this is also due to the edge of the new rings being much sharper than those on used rings.
 
It's really hard to force myself to break something. I have a tiny flat screwdriver that I used to scrape away everything I could in the grooves.
 
wentwest said:
It's really hard to force myself to break something. I have a tiny flat screwdriver that I used to scrape away everything I could in the grooves.
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Sorry, I should have said "old used compression ring". The squared end at the gap is sharp-edged and fits the groove perfectly, so you take an old ring and break it somewhere in the middle and use the end opposite the broken end.
 
The last time we put the cylinder on it felt a bit better, I was able to slide it down with my hands pushing.

Next question. The copper washers under the head nuts at the right (tach drive) end of the head. The old ones have a mark from a steel washer, probably between the head nut and the copper. Is that right?

1000000776.jpg
 
OK, got the head on, cam chain threaded through with the timing marks lined up on the cams and at the rotor, with the slack in the chain at the rear where the tensioner goes. Now for the master link. The link Frank sent me from Germany with the chain fits through fine, but there's no way I can get the side plate on the pins. I've tried on the workbench and in place and it feels like the pins are bigger than the holes in the plate. That was last week's frustration.

I ordered a different master link from 4into1 and picked it up yesterday. Today I've been trying to peen over the pin ends. I put together an old, filthy bolt and an extra thick nut and set that up with the bolt head pressing on the back end of a pin and the nut against the inside of the head to give some backing to the pin, then put a tapered point punch into the dimple on the end of the pin where the plate sits, and smacked the punch a bunch of times. The pin just laughed at me. What am I doing wrong?

I'll take a couple of photos so you can see how I set it up.

master link attempts.jpgmaster link attempts 2.jpg

The shiny little things on the chain are rare earth magnets that I bought at Harbor Freight. They stick like crazy ( I have to pull them off with a pliers) and they are holding the chain to the sprocket.
 
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Magnets are a great idea. The cross bracing in your design though is going to bend the pin before it mushrooms it out.

If you’re going with the hammer method, you’ll need something more substantial on the other side as an anvil. I’ve got the old head from a sledge that I use for a lot of that manual press stuff. You’ll also find that squarely placed sharp blows will do better than the hamhanded smash. The more square you can get both side to their pressure points, the easier it’ll go.
 
wentwest said:
Today I've been trying to peen over the pin ends. I put together an old, filthy bolt and an extra thick nut and set that up with the bolt head pressing on the back end of a pin and the nut against the inside of the head to give some backing to the pin, then put a tapered point punch into the dimple on the end of the pin where the plate sits, and smacked the punch a bunch of times. The pin just laughed at me. What am I doing wrong?
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I have typically used a bicycle chain tool to peen the pin ends with my 450k7. The smaller size relative to a motorcycle chain tool makes it easier to get it in the correct position.
 
Today, with the help of my neighbor, we got the pins peened down. I had a very old 4 pound sledge and while he held the top edge of the sledge against the two pins I hammered them down with a thin, round end punch that has a tiny dimple in its center, too. It seems to have flared the heads of the pins. Things look good and the magnets are back in their little plastic house. On to the next steps.

I don't know what I'd do without you guys.
 
New drama. It feels like the advancer is touching the heads of the 6mm screws that hold the bearing cap on to the head at the left end of the exhaust cam. They are behind the advancer. Are there supposed to be some sort of flat head screws there?
 
wentwest said:
New drama. It feels like the advancer is touching the heads of the 6mm screws that hold the bearing cap on to the head at the left end of the exhaust cam. They are behind the advancer. Are there supposed to be some sort of flat head screws there?
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Wait, are you saying there are flat head screws in the left exhaust cam bearing cover holding it to the head? The 4 screws (3 behind the advancer) should be JIS heads. Anything taller, like allen screws for example, can hit the advancer.
 
ancientdad said:
Wait, are you saying there are flat head screws in the left exhaust cam bearing cover holding it to the head? The 4 screws (3 behind the advancer) should be JIS heads. Anything taller, like allen screws for example, can hit the advancer.
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The screws that are there are JIS rounded head screws. The heads are very close to touching the back of the advancer, and I can't tell if they are touching or just close, so I'm worried. I did not take this engine apart, and it did not come with any special screws to use here, so I'm using JIS screws from my parts horde. Everything else I have that fits the threads is taller. I decided to grind down the heads just a bit, then put them in, added the advancer and turned the engine over by hand. After a few turns I took the advancer off and there was no sign of scratches, so I guess it's OK.

This is going very slowly because speed isn't my friend. There's no hurry. The next step, I believe, is to put the engine in the frame and then assemble the starter, the clutch, the rotor, the oil pump, etc. Why make the engine heavier?
 
Yeah. Getting that hunk of aluminum back in the frame is a real exercise. Funny how getting them out is always so much easier than getting them back in.
 
This engine has never been in any frame while I've owned it. It came as a partial, just a part of the stash of stuff that I got when I bought the Bomber. The engine in it right now is a K4, this one is mostly a K0 4 speed. The bike runs and rides now, but, truth be told, I don't love riding motorcycles. I'm a scooter rider, but I do love the process of problem solving old analog machinery. If this engine runs well I'll probably start thinking about selling the whole thing.
 
So after a long summer spent mostly on some major maintenance on the scooters (new head gasket on one, renewed the starter clutch on the other) I dusted off the Bomber, charged the battery and started it. Surprise, it started easily and ran well. I rode it around the neighborhood for a few miles, up and down our long steep hill, and then went farther to the gas station for a fresh gallon of high octane. The ride was very rough and bumpy feeling, and left me feeling uneasy but it really needs new tires, one is from 2005 and the other is from a year ending in 7 before the turn of the century. So I ordered the tires, new tubes and rim strips, and once they are on I can tell more about the ride.

And then it's time to try and set the rebuilt engine in the frame and move along.
 
wentwest said:
So after a long summer spent mostly on some major maintenance on the scooters (new head gasket on one, renewed the starter clutch on the other) I dusted off the Bomber, charged the battery and started it. Surprise, it started easily and ran well. I rode it around the neighborhood for a few miles, up and down our long steep hill, and then went farther to the gas station for a fresh gallon of high octane. The ride was very rough and bumpy feeling, and left me feeling uneasy but it really needs new tires, one is from 2005 and the other is from a year ending in 7 before the turn of the century. So I ordered the tires, new tubes and rim strips, and once they are on I can tell more about the ride.

And then it's time to try and set the rebuilt engine in the frame and move along.
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I spent a lot of time truing my wheels early on. I’ll probably check them again as a winter project.
 
I don’t wish to start a $===storm and there is some argument amongst ourselves.

However, I use the removeable master link from a XL175 cam chain. Perfect fit. I have around 3500miles on mine.

The reason is I had so much trouble peining the link pins I looked for, and found, a different solution.
 
Jays100 said:
I don’t wish to start a $===storm and there is some argument amongst ourselves.

However, I use the removeable master link from a XL175 cam chain. Perfect fit. I have around 3500miles on mine.

The reason is I had so much trouble peining the link pins I looked for, and found, a different solution.
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I can see that on the 175 engine as that's how they came from Honda, but on the DOHC 450? I'm sure it would be fine under normal circumstances, but I think I'll stick to rivet links.
 
Yeah, the unit I am running on is a 450 to clarify. The CB/CL 175 uses that same chain only a different length as the XL. I think it also fits the yamaha xs11.....
 
When I was struggling to peen the rivets on that timing chain, I would have jumped at the info that an XL175 used the same chain and a master link. In fact, there's still a question in my mind whether the job I did on the rivets is good enough.

This weekend I'll start the tire swapping process by getting the wheels off the bike and securing it so it doesn't tip over. When Cycle Gear calls that everything's in I'll drive them over with the Miata, top down (one in the trunk, one on the passenger seat). Their work is not always reliable but the all-in price, combined with the selection of tires to order online makes them a decent choice. Last time they put the tire on backwards in spite of all the Sharpee marks on the rim and the hub.
 
So a pair of Shinko 712's on the rims, 100/90x19 on the front, 110/90x18 on the rear, new tubes and rim strips. I put things back together yesterday and today and took it around the block. What a difference! The buckboard ride is gone, things are much smoother and in control. Now I have to take the big ride down the hill into Berkeley, loaded down with locks, cables and such to secure it if it poops out somewhere away from home. I doubt it would last long parked on a street in Berkeley. It's going to take some time to rely on it, and then pull the K4 engine and put in the K0 engine. This seems to be a lifetime project.
 
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