A Bomber barn find

All the outer covers on Honda engines have a dowel pin or two, typically two, but I'm sure whatever sealer he used has something to do with it. Generally, silicone sealer makes covers easier to remove as it usually makes the gasket break away clean and not tear into pieces, so I'd be surprised if that's what is on there.
 
Sloooooowly moving into the old engine. I finally got the right cover (over the clutch) to come unstuck and that cover is off.
The clutch is maybe some sort of aftermarket piece, because it has 6 bolts holding the plate stack, not 4. Things look clean inside, but the oil "filter" center cover piece is really stuck. I tried heating the outer but no luck yet. The center bolt came out easily enough, so the center bit is just stuck. Solved this already; I read the manual! Screw in a longer 8mm bolt, and keep turning it until the center piece pops out.

I may have asked this before, but where should I look for rings? The pistons seem to be 72.25 mm, 2 over, and the bores are 72.5, all checked with a very poor measuring device. They appear to have never been used. I'll take the pistons and the cylinders to a machinist before I order anything.

The next step is to split the cases to see what's the story inside. I expect it will be okay, but who knows?


450K0 pistons.jpg

450K0 clutch.jpg450K0 pistons.jpg450K0 clutch.jpg
 
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The clutch is maybe some sort of aftermarket piece, because it has 6 bolts holding the plate stack, not 4
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No, genuine, standard for the CB450 K0, and wanted by others to replace the 4 spring clucht in later versions, especially when the engine delivers more power then standard.
 
A few more hours spent opening things up. No surprises inside except for dried leaves and some filth. The gear seem pretty good and nothing shows obvious wear or damage. If anyone sees something I don't, please let me know.

CB450K0 Cam Chain sprocet and Crankshaft.jpgCB450K0 Gearbox.jpgCB450K0 Shift mechanism.jpg
 
Relative low miles engine, gearbox seems to be in good health. Primary shaft somewhat burned ? Check clutch inner bearing for abnormal wear. Shift-drum locator is worn, I would replace it anyway. Clean the crank as described in the thread of Teebo, clean the bearings and listen to them before decide to replace,
 
Back at it. On the parts blow-up and just looking at it the windage panel in the crankcase seems to be held in with a rod that slides in and locks it in place, held tight by the panel's tension against it. Is that all there is? I don't want to start picking and pounding on things that don't come apart the way I imagine they do.
 
wentwest said:
Back at it. On the parts blow-up and just looking at it the windage panel in the crankcase seems to be held in with a rod that slides in and locks it in place, held tight by the panel's tension against it. Is that all there is? I don't want to start picking and pounding on things that don't come apart the way I imagine they do.
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Yep, the 4 speed version is easy to remove, it's as simple as it seems to be.
 
Moving along. I'm trying to take out the shifting forks, last step before I can take the crankcases to be cleaned. How do you get the shift fork guide pins out? I have the clips off and everything else that has to be off so once the pins come out I can slide the drum out. The pins don't just fall out and I don't see any way to pull them. The magnets I have are too thick to reach in the opening.
 
wentwest said:
Moving along. I'm trying to take out the shifting forks, last step before I can take the crankcases to be cleaned. How do you get the shift fork guide pins out? I have the clips off and everything else that has to be off so once the pins come out I can slide the drum out. The pins don't just fall out and I don't see any way to pull them. The magnets I have are too thick to reach in the opening.
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Take a big magnet with a small bolt stuck to it to touch the pin. Got to loosen the rust/gunk bond in there. Ice pic or tiny eyeglass flat blade screwdriver to tap and pry around it too.
 
ballbearian said:
Take a big magnet with a small bolt stuck to it to touch the pin. Got to loosen the rust/gunk bond in there. Ice pic or tiny eyeglass flat blade screwdriver to tap and pry around it too.
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Those doughnut magnets from old base woofer drivers are hard to pull off my refrigerator door. :)
 
ancientdad said:
Look at this picture, it shows the sloppiness in the roller center due to wear because the roller is far off-center on the shaft.

View attachment 27634
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Commonly more of an issue on the 5 speed mechanisms but clearly some wear on this 4 speed. Good eye by Jensen to catch it and good explanation by Tom to show it. I wonder if these rollers are NLA like the 5 speed pizza cutter? I bet I could replace the rivet in one of these just as easily as I do in the others if anyone ever needed one repaired.
 
12ozPBR said:
Commonly more of an issue on the 5 speed mechanisms but clearly some wear on this 4 speed. Good eye by Jensen to catch it and good explanation by Tom to show it. I wonder if these rollers are NLA like the 5 speed pizza cutter? I bet I could replace the rivet in one of these just as easily as I do in the others if anyone ever needed one repaired.
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While that one certainly needs to be replaced, I don't think it would have the detrimental effect on shifting that the pizza cutter does on the 5 speed, probably just a sloppy neutral location. The one I have for my 4 speed bottom end is in much better condition than that one above is, though it does have a little slop. I'm sure you could repair those as well, but I'm wondering just how much demand there would be.
 
Seems like CMSNL has them now, about $9.31, $30.00 all in with shipping. It's #24430-283-000. I don't think you should change your retirement plans because you can make the big bucks on these stoppers. I'll scrounge around for other stuff to order from them so at least the shipping cost is spread over a small bunch of parts.
 
Another thing. The cylinders are overbored on this 4-speed engine, and the pistons are marked with "3.00". I've tried and I think the bores are about 72.75 and the piston is 72.53 at the top, but 72.7 at the base. All these measurements are done with a Harbor Freight vernier electronic caliper so the accuracy is questionable. They look new. One piston has its rings but the other does not. Where do I look for rings?
 
wentwest said:
Another thing. The cylinders are overbored on this 4-speed engine, and the pistons are marked with "3.00". I've tried and I think the bores are about 72.75 and the piston is 72.53 at the top, but 72.7 at the base. All these measurements are done with a Harbor Freight vernier electronic caliper so the accuracy is questionable. They look new. One piston has its rings but the other does not. Where do I look for rings?
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Though the numbers aren't exactly what I'd expect based on the '3.00' stamping, that suggests these are aftermarket 3mm oversized pistons - S12 in Honda terms and the factory only went to S4, 0.25mm (.010") each increment - so finding rings for those could be challenging since the 4 speed pistons are slightly different.
 
Should I look at rings for other Hondas that may have the correct dimensions? For example, rings for a 250 single or even a 1000cc 4? Or how about rings for a Yamaha or other bike?
 
The issue would be if the rings from other pistons would fit the grooves in your pistons, I don't know that the thickness is standardized. I know I've previously seen 73mm piston sets but I just ran a search and could not find any. BTW, the early XL250 had a 74mm bore but with a 4 valve head and almost flat top pistons.
 
ballbearian said:
I'd check these guys too. OS head gaskets and piston kits, mostly Wisco.

Honda CB 450 | Andrews Motorsports

Honda CB 450 Parts | Andrews Motorsports
andrewsmotorsports.mybigcommerce.com andrewsmotorsports.mybigcommerce.com
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They have 73.5mm rings, a bit large for him to file ends gaps, but he'll need the oversize head gasket for sure if he uses those pistons. Sadly they want $70 for a head gasket, a bit steep. Maybe a used set of cylinders and stock pistons/rings would be cheaper.
 
ancientdad said:
They have 73.5mm rings, a bit large for him to file ends gaps, but he'll need the oversize head gasket for sure if he uses those pistons. Sadly they want $70 for a head gasket, a bit steep. Maybe a used set of cylinders and stock pistons/rings would be cheaper.
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I was wondering about that.
 
wentwest said:
I was wondering about that.
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Cylinders will interchange between 4 speed and 5 speed, the only concern might be the fit of the later pistons in the 4 speed head/combustion chamber. I know the early pistons were slightly different, just not sure if the later pistons would be a problem.
 
LongDistanceRider said:
Might check and see if he still has pieces https://www.vintagehondatwins.com/f...ds/cb450-engine-parts-free-to-good-home.9672/
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I did, he does, YAHOO!

So, now I'm putting together something I did not take apart, and for me that's a challenge. Putting the valves into the heads. The logical sequence seems to be: valve slides in through the guide, valve stem seal slides down over valve stem, clip that holds down guide and seal gets bolted on. But the manual and parts diagrams don't really help. Is my idea right? Or does the seal go over the clip?
 
wentwest said:
But the manual and parts diagrams don't really help. Is my idea right? Or does the seal go over the clip?
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This should help Bob, surprised you hadn't seen it yet.

DOHC 450/500T head assembly

Since the 450 and 500T have the only cylinder head with torsion bar valve springs, it is one of the more unique engines to rebuild among our vintage Honda twins. Since words don't often tell the full story of how to assemble the head, and particularly since there are many videos out there...
www.vintagehondatwins.com www.vintagehondatwins.com
 
ancientdad said:
This should help Bob, surprised you hadn't seen it yet.

DOHC 450/500T head assembly

Since the 450 and 500T have the only cylinder head with torsion bar valve springs, it is one of the more unique engines to rebuild among our vintage Honda twins. Since words don't often tell the full story of how to assemble the head, and particularly since there are many videos out there...
www.vintagehondatwins.com www.vintagehondatwins.com
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Like you wrote there are so many videos that show so many bad practices, I just started to put it together with logic and parts blow-ups and the FSM. I'll start referring to your write-up.

This is some kind of fun. I'm enjoying the challenge of carefully doing a 3-D jigsaw puzzle.
 
I ordered a new timing chain from Frank in Germany and it came the other day. Only now I'm unsure about it. The one I got says it's a DID 219T Bush Chain (128LE), with a master link, and there seems to be a DID 219T Roller Chain for sale, too. Which is correct? I'd like to know before I even open the box.
 
Thanks for the speedy reply. I also saw this one for sale; it's a Roller, whatever that means. Anyway, it seems not for a CB450. And your experience is enough for me.

1707252021708.png
 
My mechanical background starts itching, thus time for some clarification about chains in general:


Exploded view of a roller chain:
FIG_10-thumb-590x466.jpg

The roller moves freely around the pin, that's why it's called a roller chain.

Exploded view of a bush chain:

images.jpeg

This chain doesn't have rollers but instead, it has bushings, that why it's called a bush chain. The problem is that in most pictures (like this) the word roller is used, what is misplaced / misleading for a bush type chain.


A roller chain is more complex due to the extra roller, but needs less energy due to less friction. Roller chains are more expensive than non-roller chains (more parts). steuerkette (German) or literal "direct chain" means cam chain. Cam chains are normally bush chains, there is oil enough around to lubricate the inner bushings. And, a roller chain has a smaller diameter pin, so weaker than a bush chain (outer diameter is the same). Drive chains are roller chains, the grease is closed off by mechanical tolerances or O-rings, X-rings etc.

I use a standard roller chain with clip for the starter, works better than a bush chain (less lubrication in that area).
 
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jensen said:
My mechanical background starts itching, thus time for some clarification about chains in general:


Exploded view of a roller chain:
View attachment 29350

The roller moves freely around the pin, that's why it's called a roller chain.

Exploded view of a bush chain:

View attachment 29349

This chain doesn't have rollers but instead, it has bushings, that why it's called a bush chain. The problem is that in most pictures (like this) the word roller is used, what is misplaced for a bush type chain.


A roller chain is more complex due to the extra roller, but needs less energy due to less friction. Roller chains are more expensive than non-roller chains (more parts). steuerkette (German) or literal "direct chain" means cam chain. Cam chains are normally bush chains, there is oil enough around to lubricate the inner bushings. And, a roller chain has a smaller diameter pin, so weaker than a bush chain (outer diameter is the same). Drive chains are roller chains, the grease is closed off by mechanical tolerances or O-rings, X-rings etc.

I use a standard roller chain with clip for the starter, works better than a bush chain (less lubrication in that area).
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In all my bicycle shop years, I never encountered a bush chain and was unaware of this. Thank you Jensen.

The 160's and 305's use the 219H, I believe. Are these not roller chains?
Also, the 305's use an unusual chain for their primary drive. I had noticed that there is no ability for those 'bushes' to rotate and so wear is an issue there.
 
OK, another simple question. The chain I received is continuous. Frank did send a new master link, too. Am I supposed to grind off the peened over ends of the pins on one link? Any particular link? Is one side better than the other to grind?
 
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wentwest said:
OK, another simple question. The chain I received is continuous. Frank did send a new master link, too. Am I supposed to grind off the peened over ends of the pins on one link? Any particular link?
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Did he send the press-on side plate master link, or a rivet link? I just can't bring myself to trust a press-on link, so I buy rivet links from 4into1 and use them. Is the chain he sent 128 links? I notice it didn't say so on the front of the package.
 
ancientdad said:
Did he send the press-on side plate master link, or a rivet link? I just can't bring myself to trust a press-on link, so I buy rivet links from 4into1 and use them. Is the chain he sent 128 links? I notice it didn't say so on the front of the package.
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He sent a rivet link, and all the labeling says it's a 128 link chain. I haven't counted them, but I will.
 
ancientdad said:
Did he send the press-on side plate master link, or a rivet link? I just can't bring myself to trust a press-on link, so I buy rivet links from 4into1 and use them. Is the chain he sent 128 links? I notice it didn't say so on the front of the package.
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Is a press-on the same as a spring clip type?
 
ballbearian said:
Is a press-on the same as a spring clip type?
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That's what I assumed. The link I got has two posts that I'll punch down (flare) to hold the plate on. But I still have the same question - am I supposed to grind one of the existing small plates off?
 
You cannot assemble a closed chain on a 450, you have to rivet or press. If you got a closed chain, it's not specific for a 450 anyway.
 
wentwest said:
am I supposed to grind one of the existing small plates off?
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Yes, in order to use it you'll need to carefully grind the heads of the pins on one link which will be replaced with the rivet master. I have a new chain from 2 wheels Frank in my garage, unopened, and I'll check it later today to see if mine is endless. I honestly can't recall if the ones I bought from him previously were endless or not as delivered. It does make me wonder, though, if the chain in your package is actually a 128 link because the 350 chain of 94 links comes endless and someone here accidentally was shipped a 350 chain when ordering a 450 chain in the past.
 
I got my CB450 chain from 2wheelsFrank about a year and a half ago and it is 128 link and is not endless. I bought two rivet type links from Partzilla because you know sometimes mistakes happen!
 
I checked the brand new chain I bought last year for my drag bike engine and this is what the label looks like. And it's also endless. I wonder if the "E" in LE means endless. Not that big a deal, just another step to do before using it.

219T-128.jpg
 
ancientdad said:
I checked the brand new chain I bought last year for my drag bike engine and this is what the label looks like. And it's also endless. I wonder if the "E" in LE means endless. Not that big a deal, just another step to do before using it.

View attachment 29454
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And that's exactly what I got. I've tested the grinding idea on an old DID 219 chain that I want to replace and so far I've ground the rivits down even with the link but it won't budge. I'm getting frustrated.
 
If it doesn't pop apart easy grind deeper, you're going to pitch that outer link anyway.

I went all the way back and read this thread from the beginning because it was so enjoyable.
 
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