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CB450 Restoration

tyskyking

tyskyking

Veteran Member
Joined
Feb 28, 2024
Total Posts
103
Total likes
135
Location
Stuart, FL
I got some time this morning to work on the bike. I did a compression test with my cheap Harbor Freight Compression gauge. I did it first two weeks ago and got disappointing numbers so I thought I’d try again. Same result. At WOT and Open Choke left cylinder made 90 pounds and right around 100. So issues there. The bike also has electrical issues. Verified the battery I got with it was charged and showed 12 volts. Hooked up the leads and nothing is getting power. No headlight, accessories, & no spark. Took the tank off and drained to investigate electrical in the future. Seems like it was rewired for the cafe racer conversion and it’s a bit of a mess. Not sure if best option at this point is to start going through with test light and doing electrical or diagnosing possible top end issues. I wanted a project and it seems I got one. 😁 At least the tank looks decent enough..

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Well, you have a mess under the seat for sure. All factory mounting locations for stock sidecovers are gone along with the battery box. Looks like an aftermarket rec/reg combo unit so that may be usable, but in order to use stock sidecovers you'll need to get some donor tabs and get them welded in the original locations, along with the missing sections of the rear of the frame so you can mount a stock rear fender if you plan to. The wiring harness is down the wrong side of the frame but looks to be mostly intact, though once you get all the garbage in the battery area unzip-tied so you can see what you have and what you need better, you'll know more about how to proceed. Also, the right cylinder would never have fired with the points cover on the engine the way the right set of points is wired, the blue terminal would have shorted on the cover.

Oh, and it looks like the left exhaust valve adjuster shaft might be oriented incorrectly, can't see the index mark but it looks out of place as it is. Need a clearer close-up of that to be sure.
 
RE: Compression. Until you can do a tune up and set the valves and get the bike running and heat cycled, those numbers may not be bad at all. Sticking rings from the bike sitting and valves not sealing from rust or carbon could be some of those disappointing results causes
 
Your HF gauge appears to have a rather long rubber hose which will also contribute to low readings.
 
tyskyking said:
I’ll take it. PM me for details. Thanks!
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Ok. I’ll take a couple pics of it later and post them. I have the battery box assembly, the side cover bolts and screws. It has all the clamps and fasteners to attach the box as well. I’ll send a pm with price. Edit. I have the plastic filter covers also but it won’t include the air filters or the side covers.
 
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2wheel said:
Ok. I’ll take a couple pics of it later and post them. I have the battery box assembly, the side cover bolts and screws. It has all the clamps and fasteners to attach the box as well. I’ll send a pm with price.
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And remember, he hasn't yet reached the magic number of 10 posts so you will have to initiate the PM exchange. (y)
 
That electrical is basically trash and will likely need to be redone almost end to end if you’re going to try and bring it back to stock. However, your immediate issue likely belongs to what appears to be a very abraded AC Gen wire running to tha reg/rec. (blue)

In which case, that inline fuse is very likely popped. (Yellow)

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I’ve got the air cleaner shells (no filter media) and a few odds and ends like a rear fender and some trim pieces if you want them.
 
Also, y’all would know best but it appears the tank and side covers I have are from a K6 or later based of the ID thread but the serial is of a K5. Also, a 72 on title but 10/71 build.

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EzPete said:
That electrical is basically trash and will likely need to be redone almost end to end.

I’ve got the air cleaner shells (no filter media) and a few odds and ends like a rear fender and some trim pieces if you want them.
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I figured as much. Thanks for the picture edits. I do have the air cleaners but the filters are shot. I also have the rear fender. I have to inventory all the parts I have when I get more time and see exactly what I need. Thanks!
 
Actually, the candy orange with the large multi-stripes is from the K7, candy orange wasn't one of the two original colors for the K6. And for the year titled, it's typical in the US for anything sold after September 1st of a given year to be titled the following year so a build date of October '71 would have been titled '72 (at least here in Florida). My CL450K5 is titled '73 but it's really a '72 like yours. Since all the painted parts interchange through that period, it's easy to make one look a year or two different.

I'd wait until pulling the wiring harness and inspecting it to completely condemn it, the changes could be limited to the battery box and rec/reg wiring/area. If you do decide to replace the harness, Sparck Moto (as well as Vintage Connections, both owned by VHT member @Sonreir, sells top quality wiring needs and the best value in rec/reg combo units) is your best choice for quality products and great support for them.
 
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ancientdad said:
in order to use stock sidecovers you'll need to get some donor tabs and get them welded in the original locations, along with the missing sections of the rear of the frame so you can mount a stock rear fender if you plan to.
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The bike came with this donor cut rear frame. I suppose I can transplant the tabs and fender brackets. Are there any more I need? I’ve got a battery box coming from @2wheel I also have the tool box.

Thanks for the electrical links. I have to sort out the wiring mess!

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Well you're halfway there. That frame section only has the rear sidecover tab, there's another one on each side, forward of the one shown on your frame cut. Also, if your seat is rear hinge then you're good, and I see in one of the pics that the rear hinge mount is there. BUT that also causes some confusion, since your frame tag says it's a K5 which had the side hinge and I see a side hinge seat on the shelf in your garage...

K4 seat
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K5 seat
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and to make matters worse... K5 frame, allegedly, showing rear seat mount (likely a parts fiche mistake)
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Slowly breaking down the bike. Pulled the engine and threw it on the stand. I plan to tune it up per the FSM once I get more time. In the mean time doing more research on the DOHC top end to prep for inspection.

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Started getting into the engine top end. It's been going pretty smooth. A couple things I noted.. When I dumped the oil pan, the oil had a gas-like smell so I'm wondering if gas was getting in there. Viscosity seemed a little light too. There were small metal shavings behind the contact breaker plate. Also, the intake camshaft has a tore up looking seal on one side. Not sure if that's normal. Any torsion bar advice before I move forward? Never worked with them before.

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tyskyking said:
the oil had a gas-like smell so I'm wondering if gas was getting in there
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If the oil had a fuel smell, either the petcock was left on or it is not shutting off and leaking past the closed valve and letting the carbs seep into the intake ports, then past an open valve and down into the bottom end. Always turn off the petcock when you turn off the key, and never run the engine with fuel-smelling or diluted oil or damage can happen.
tyskyking said:
There were small metal shavings behind the contact breaker plate.
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As well as that flat washer laying in the points base at arrow #3, and the missing circlip on the pivot post for the advancer weight at arrow #2. And, did you remove the bolt and special hardened washer from arrow #1 spot?

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tyskyking said:
Also, the intake camshaft has a tore up looking seal on one side.
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Not a seal, they're rubber damper rings to help quiet the cam chain noise. They always come apart, no point in replacing them as they're not necessary and you'll never know the difference.
tyskyking said:
Any torsion bar advice before I move forward? Never worked with them before.
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Depends on how far you plan to disassemble the head. If you plan to take it completely apart and have the valves, seats and guides checked by a machinist, then you'll need to know how to properly disassemble them. Here is an assembly thread for the DOHC 450 head, just do things in reverse. ALWAYS ask questions first before attempting to take something apart that you have the slightest question about to avoid doing damage.
 
Cylinder head completely apart now. Torsion bars were pretty simple to remove. Followed guidance online and went slow. No issues there.

Valves look okay. Straight to the eye. Lots of carbon. The valve seats in the head don’t look great to me, but I don’t have the years of experience like some on this board so sharing the pics.

Going to take valve measurements when I have more time.

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Always hard to tell for sure when they're that dirty. I put all in the gas pot (parts cleaner) to get rid of the oiliness, then break out the drill with the wire brushes on anything steel (valves, combustion chamber and seats). Just stay away from aluminum surfaces with the steel wire brush.
 
tyskyking said:
There were small metal shavings behind the contact breaker plate.
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This makes me think about the CB450 I had back in the 70's that the advance mechanism disintegrated on me on I-10 in the desert around Palm Springs or Indio I guess. I had dissembled the advance mechanism for some reason, probably to lube it, and forgot to put the thin shim in that goes between the advance backing plate and cam lobe. I hiked a few miles to get to a phone and call for a pickup from a friend and we worked on it and got it running again. I can't remember if we had to replace the complete cam shaft or just the advance mechanism as that has been a long time ago. At the time there was always a lot of cold beer involved in vehicle repairs.
 
Looking at the valves, the shiny sections are where the valve actually was making contact with the seat. The second set, exhaust I think, look to have barely been seating at all.
Valve seat pictures pretty much confirm the above.
Valve seats need to be ground, likely the valves need replacement.
You might consider shipping the head to Chris at Schumann Motor Works https://www.facebook.com/p/Schumann-Motor-Works-100054197273586/
 
tyskyking said:
Cylinder head completely apart now. Torsion bars were pretty simple to remove.
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Be careful about video advice from the internet, plenty of backyard hacks out there.

My sincere apologies for forgetting to post this link previously after mentioning it, I remembered later but couldn't recall which thread it would have been for. It might help with your reassembly.

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
 
LongDistanceRider said:
The second set, exhaust I think, look to have barely been seating at all.
Valve seat pictures pretty much confirm the above. Valve seats need to be ground, likely the valves need replacement.
You might consider shipping the head to Chris at Schumann Motor Works https://www.facebook.com/p/Schumann-Motor-Works-100054197273586/
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Thanks for the link. Yes, I thought the exhaust valves didn’t really have any clean area on them. So, partially open or unseated on the power stroke? Or, just the seat in the head is that bad? Any point in trying to clean the head before sending it out? I got some Formula 88 for soaking it yesterday as everyone has heavy carbon on it.

Also, on another note. I was reading another thread about serial numbers. I forgot the PO said the bike had a closely numbered frame & engine and there was something significant about that. I didn’t really think about as it was a FB marketplace deal. Didn’t, remember until I saw the other 450 thread mention it. But my frame & engine are 8 digits apart.
 
ancientdad said:
Be careful about video advice from the internet, plenty of backyard hacks out there.

My sincere apologies for forgetting to post this link previously after mentioning it, I remembered later but couldn't recall which thread it would have been for. It might help with your reassembly
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No worries, I found the assembly thread you were referencing. I’ve mostly been following the CMC videos and the FSM. The CMC videos are helpful though because I’m a visual person and 50+ year old B&W aren’t always the best.

ancientdad said:
That's incredibly rare, it's typically a few hundred or more, sometimes in the thousands apart.
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I was told it meant it was early in the production run for the year. Any truth to that?
 
My frame and engine serial numbers are 24 numbers apart and that is why I am kinda bummed about the damage to the top engine case.
 
Took my frame down to Jessie at Hex Moto in Boynton for some fab work. He added back the seat hinges, lock bracket, side cover tabs, fender bracket and helmet holders from my donor. Dropped it off and he had it done next day! Next is media blast and powder coat.

Sent the head off as well to get overhauled. Getting into the lower engine now as time allows.


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A nice thing about the swiveling engine stand is you can invert the engine and with a few soft hits of the rubber mallet between cylinder they slide right off. IMG_8904.jpeg

Found what I think is remnants of the cam dampener rings in the crankcase cover?

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tyskyking said:
Took my frame down to Jessie at Hex Moto in Boynton for some fab work. He added back the seat hinges, lock bracket, side cover tabs, fender bracket and helmet holders from my donor. Dropped it off and he had it done next day! Next is media blast and powder coat.
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I hope you also mocked-up the tank and seat together so you can be sure of the seat-tank fit.
tyskyking said:
Sent the head off as well to get overhauled. Getting into the lower engine now as time allows.
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Did you send the head to Schumann? You'll be pleased if so.
tyskyking said:
Found what I think is remnants of the cam dampener rings in the crankcase cover?
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Or the cam chain center roller or tensioner roller. Don't bother with replacing the damper rings, they'll just get hard and deteriorate again and fall apart. You won't notice any additional top end noise without them.
 
ancientdad said:
I hope you also mocked-up the tank and seat together so you can be sure of the seat-tank fit.

Did you send the head to Schumann? You'll be pleased if so.
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Well I suppose that would’ve been the smart thing to do, but I’m having the dents popped on it at another shop so I didn’t have it. All he does is vintage bikes so I figured he’d say something if he needed it. I’ll take it when I pick it up and make sure the fit is good.

Yes, shipped to Schumann. I paid the price for the shipping to Oregon but I trust your guys recommendation.
 
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tyskyking said:
Well I suppose that wouldn’t been the smart thing to do, but I’m having the dents popped on it at another shop so I didn’t have it. All he does is vintage bikes so I figured he’d say something if he needed it. I’ll take it when I pick it up and make sure the fit is good.
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Well, if he does vintage bikes often he probably has a pretty good idea where things went and he may have had some clues left on the frame as well. I was just thinking about the seat hinge mounts and lock mount so the seat would still fit to the tank like it did when new.
tyskyking said:
Yes, shipped to Schumann. I paid the price for the shipping to Oregon but I trust your guys recommendation.
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I have an $800 example of Schumann's work in my garage, it's worth the shipping costs.

https://www.vintagehondatwins.com/forums/proxy.php?image=https%3A%2F%2Fi.imgur.com%2F4IvEGEb.jpg&hash=d342914fbb7406164054554c6c4e5874
 
Any tried and true techniques for:

1) Getting these dang 52 year old gaskets removed, which are stuck on like cement. I'm currently soaking everything in formula 88 to try and soften them.
2) Getting the rotor bolt broken free. I only have rubber oil filter "wrenches" which keep slipping.

Thanks!
 
tyskyking said:
Any tried and true techniques for:

1) Getting these dang 52 year old gaskets removed, which are stuck on like cement. I'm currently soaking everything in formula 88 to try and soften them.
Click to expand...
Few tricks for that aside from hard work, it's the least fun part of anything you'll do to your bike. Imagine doing it for a living, it gets old fast. Sometimes paint remover helps, others will have suggestions but mostly just carefully scrape scrape scrape.
tyskyking said:
2) Getting the rotor bolt broken free. I only have rubber oil filter "wrenches" which keep slipping.
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If you have an electric, cordless or air impact wrench it comes loose easily. Though you could use a hand impact driver, you don't want to hit the rotor bolt with hammer force because it can weaken the magnetism in the rotor.
 
ancientdad said:
If you have an electric, cordless or air impact wrench it comes loose easily. Though you could use a hand impact driver, you don't want to hit the rotor bolt with hammer force because it can weaken the magnetism in the rotor.
Click to expand...

I figured as much. If the formula 88 doesn't help, I'll try Citri-strip overnight...

I tried my 20v impact driver, but it just made a lot of noise. Seems pretty torqued on there. I have my old trusty 4' galvanized pipe but don't have anything to hold the rotor to counter it.
 
tyskyking said:
I tried my 20v impact driver, but it just made a lot of noise. Seems pretty torqued on there. I have my old trusty 4' galvanized pipe but don't have anything to hold the rotor to counter it.
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Surprised the 20v impact doesn't do it. Put a penny between the primary drive gears to hold the crankshaft for the breaker bar. BTW, it's normal (right-hand) thread, not left.
 
That is a great point!

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Also, for the oil filter nut. Do I try to flatten all the pawls? I only noticed the tongue in the 12 o’clock position pushed down into the nut channel. The FSM says “paws” plural so I imagine I have to push them all back.
 
The nut has a rounded side intended to face the 'lock tabs', and usually only one is bent into the nut to retain it. Hard to be sure from your picture but it looks like the nut might have been put back on upside down previously, so bending all the tabs down is fine and might help in this case. Once you get the nut off you can bend the lock tabs slightly upward from flat to make it easier to use it when you put things back together. Looks like someone used a blunt chisel to loosen it previously. The wide notch that goes over the 2 ribs in the cup at the 5 o'clock position might be bent and need some 'repair'
 
I would only push back the pawls or tabs just enough to loosen the nut. On my donor engine I removed the nut OK but I spent about 2 hours getting the locking washer out without damaging anything. Seemed like the PO had flattened all the tabs a bit and the pushed it in locking it inside the rotor.
 
RobMan said:
I would only push back the pawls or tabs just enough to loosen the nut. On my donor engine I removed the nut OK but I spent about 2 hours getting the locking washer out without damaging anything. Seemed like the PO had flattened all the tabs a bit and the pushed it in locking it inside the rotor.
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Once the nut is off you can simply pull the filter cup off and everything inside it comes off with it. Once off the end of the crankshaft it's all loose parts.
 
So this oil filter nut is still giving me trouble. I’m not sure what’s impeding its removal. I backed off all the paws with a flathead and hammer. The only thing I visibly see is this tab that slots in the grove in the cup that seems to be in contact with the nut but I can’t fathom how that would prevent any rotation. Any ideas?

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Also picked up my frame from the shop yesterday and he had this 350 on the stand. So here’s a pic for eye candy.
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It looks like one tab is still in the bottom groove of the nut. No? Maybe that's an illusion. Can you get a picture looking straight at it?

The washer has lots of tabs.

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