Author Topic: 1967 CB450K0 Black Bomber Rebuild - By Royhall  (Read 38307 times)

Online Laverda Dave

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #45 on: March 09, 2019, 10:23:12 AM »
Looking superb Roy. A great read of a rebuild, keep the commentary and photos coming.
We'll done to Ash for coming to the rescue with the barrels to keep the build going.
This is such a great forum with members helping each other out, great stuff 👏.
1976 Honda 400/4
1977 Rickman Honda CR750
1999 Honda VFR 800FX
1955 750 Dresda Triton
1978 Moto Morini 350 Sport
1978 Honda CB400/4 'Rat' bike
1982 Laverda 120 Jota

Offline JamesH

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #46 on: March 09, 2019, 12:13:48 PM »
Superb rebuild brilliantly explained. Keep it coming Roy..

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #47 on: March 09, 2019, 09:42:00 PM »
Looking great Roy and fantastic attention to detail and great explanations.

I was told by a Bomber Guru (who owns quite a few and restored and sold even more) that the 4-speed crank bearings were a carry over from the ones used in the Honda racing engines and that the later 5-speed crank bearings were problematic for the K1 and there were quite a few part number changes before the problem was sorted out.

Hope to pop in for a cuppa (or 'brew' as you guys call it  ;D ;D) when myself & Cathy are next over your way.
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline royhall

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #48 on: March 10, 2019, 10:15:06 AM »
Looking great Roy and fantastic attention to detail and great explanations.

I was told by a Bomber Guru (who owns quite a few and restored and sold even more) that the 4-speed crank bearings were a carry over from the ones used in the Honda racing engines and that the later 5-speed crank bearings were problematic for the K1 and there were quite a few part number changes before the problem was sorted out.

Hope to pop in for a cuppa (or 'brew' as you guys call it  ;D ;D ) when myself & Cathy are next over your way.
Your welcome anytime Ash.
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline royhall

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #49 on: March 16, 2019, 09:47:01 AM »
Now this is the part where I got all excited and forgot to take some pictures so a description will have to do. When I stripped the engine I found a bit of a mess in the cylinder head. It had a total of 12 stripped threads and a stuck exhaust valve that was very stuck. A bit of a dirty gummed up mess all round.

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I considered getting a replacement head but feared that it may be as bad as the one I have. So decision made, I will restore this one. After loads of penetrating oil soak and a good bit of heat the stuck valve gave up and came out. The other three slid out easily. After a total strip and degreasing the head was vapour blasted, it came up really nice.

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Took the head to the local machine shop guy that I use to have the valve guides replaced and the seats re-cut. Whilst it was there he either Helicoiled or fitted brass inserts to the 12 damaged threads. I took a while deciding what to do about the valve guides as there are a number of different items available for this engine. In the end I went to a fair bit of trouble located the correct for the year Bomber items, as you will see later this turned out to be an error.

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One of the guides is radiused up to a sharp edge and this is the correct part for a 1967 Bomber and the one I used, the other has a plain diameter end and this is for the later models.

The guides were fitted and reamed and the seats re-cut. I managed to source 4 new valves that required virtually no lapping in as the re-cut seats were close to perfect. Thats always a relief to me as I find that grinding in job quite boring. I fitted the valves and re-fitted all the torsion bar springs. The first one I found very fiddly to do in such a small space, but after I got it figured out the other three were quite simple. After cleaning and checking the seemingly endless array of cam chain guide wheels I refitted the parts to the head.

Now were at the point where I forgot to take the pictures, sorry.

I fitted the head using a genuine Honda gasket and oil seals, and torqued it down in stages using new nuts and washers. The cam cover studs look to be at an angle, they aren't it's a weird optical illusion in that picture.

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That is one very tall engine. I have a fairly large monitor on my PC and that picture still needs scrolling to see it all.

The problem with the stripped threads arose from the cam covers being held with 8 plain bolts. The constant removal of the cam covers has simply worn out the threads. As some of the other threads are a bit worn plus the problem of Helicoils coming out with the bolts, I decided to come up with a different solution. In the end I obtained some extra long 6mm stainless grub screws which I screwed into the head to check the lengths. The two sides are different lengths due to the fitting of a breather plate on the intake side. After bottoming them out I checked they were all the same lengths then removed the and cut them down one side at a time.

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You will see the finished idea in pictures later on in the build but basically I can hold the stud in place with an allen key whilst I undo a nut with a spanner. That way the thread in the head is not being used and I can easily change a stud if required. This fix will probably upset the purists but it needs to be functional first, then being correct is a second consideration to me. If it's worn out it's worn out, and at least this way I save the engines correct head from the scrap heap.

More soon.
« Last Edit: March 16, 2019, 10:08:02 AM by royhall »
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #50 on: March 16, 2019, 10:00:46 AM »
Very good rebuild thread Roy.

Impressed with how flat and perfectly sealed that original head gasket face was in the first picture above.

Offline royhall

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #51 on: March 16, 2019, 10:11:18 AM »
That face required no work whatsoever except a good clean, it was about the only thing on the head that was okay. I think it may be due to a fairly thick gasket, a small area, and eight large studs holding it down. I will be well pleased if I have got a good a seal again.
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Online Laverda Dave

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #52 on: March 16, 2019, 10:54:56 AM »
Fantastic progress Roy and I like  your idea of using the grub screws, practical and a worry free mod when you are giving the engine the beans.
That is one tall engine! The Laverda triple engine is very tall and is nicknamed 'the block of flats', the Honda engine is just as tall! A Jota is also known as  the world's fastest lorry due to its height and weight!
Keep posting updates.
1976 Honda 400/4
1977 Rickman Honda CR750
1999 Honda VFR 800FX
1955 750 Dresda Triton
1978 Moto Morini 350 Sport
1978 Honda CB400/4 'Rat' bike
1982 Laverda 120 Jota

Offline royhall

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #53 on: March 17, 2019, 09:04:41 AM »
Just a couple of extra shots of the cylinder head before I move on.

Note that the head hold down nuts are just normal full nuts with steel washers except for the two on the right hand side. These two are domed nuts with copper sealing washers as the two right hand drillings are used as pressurised oil supply tubes to supply the cams with lubrication.

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I don't have much time today so I shall continue another day. Cheers.
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline MrDavo

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #54 on: March 17, 2019, 10:48:09 PM »
I worried after reading the last post, I can’t check right now (I’m up a French Alp) but I’m pretty sure that my CL450 has 8 of the domed nuts holding the head down.

The CMS online parts book shows, like your bike, two domed nuts and six plain, quite why and when my bike got eight domed ones is lost in the mists of time, however as long as it has the right nuts on the two oil feed studs, which it has, as long as the other six aren’t bottomed out (hard to check) there shouldn’t be a problem.
1969 Honda CL450 'Scrambler'
1974 Kawasaki Z1A
2005 Harley XL1200R Sportster
1985 Porsche 911 3.2 Carrera Sport
1978 VW Bay Window camper van

Offline royhall

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #55 on: March 18, 2019, 03:02:35 PM »
I worried after reading the last post, I can’t check right now (I’m up a French Alp) but I’m pretty sure that my CL450 has 8 of the domed nuts holding the head down.

The CMS online parts book shows, like your bike, two domed nuts and six plain, quite why and when my bike got eight domed ones is lost in the mists of time, however as long as it has the right nuts on the two oil feed studs, which it has, as long as the other six aren’t bottomed out (hard to check) there shouldn’t be a problem.
Don't panic Dave. Mine had eight rusty dome nuts on as well when I got it. Some people fit them because they look good but that is not standard. Only the right hand stud holes carry oil so the others are okay with a plain steel washer and plain nuts. From memory I think all the studs protrude through by the same amount. You did fit copper washers under the two right hand side nuts didn't you?
« Last Edit: March 18, 2019, 03:05:12 PM by royhall »
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline MrDavo

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #56 on: March 18, 2019, 05:04:17 PM »
You did fit copper washers under the two right hand side nuts didn't you?

Oh yes, and checked that oil was coming up the studs.

Good to see my bike isn’t the only fashion victim, it was probably during its 1970’s metallic purple and ape hangers phase.
1969 Honda CL450 'Scrambler'
1974 Kawasaki Z1A
2005 Harley XL1200R Sportster
1985 Porsche 911 3.2 Carrera Sport
1978 VW Bay Window camper van

Offline royhall

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #57 on: March 24, 2019, 10:01:27 AM »
Now working on the sides of the engine.

When the bike arrived it was badly fitted with a starter motor from a later model, K1 onwards. The original motor for the K0 is a Kukasan item that is longer in the body and completely unavailable. After the K0 the upper crankcase was modified to take the shorter bodied starter. I considered stripping the rear casting off the motor and having two extended aluminium legs welded on. After some thought I decided to leave the motor stock in case it ever required changing, so I made up an extended mounting plate just to see how it looked. I don't think it came out too badly so I have decided to go with it.

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The original starter drive chain was so stretched and loose that there is evidence on the casing where it has been making contact. Another show of how poor the maintenance has been on this engine and how the low mileage on the odometer does not tie up with the wear in the engine. As I mentioned earlier in this thread, I am sure this engine does not belong in this bike and the engine number was deliberately snapped off due to this.

After a long search I came up with a NOS starter chain and paid a hefty price for it, £80. I was going to get a length of the correct size chain and a soft link and make one up but this popped up before I had a chance to do it.

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Before fitting the stator I gave it a good clean as it was covered in the same black goo that had covered the engine. Whilst cleaning it I found that the wiring was in a terrible state with bodged repairs around the rubber sealing block. I consulted Ash (our resident electrical expert) who suggested I go with a later item that also has encapsulated coils. The plug wiring would be different but that can be modified further on in the build.

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Good old DK came through with a good stator with good wiring at a decent price. To be honest DK seem to be awash with later 450 parts but a bit low on actual Bomber bits. Anyway it fit perfectly first time so looks like Ash's idea is a good one.

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After getting the stator case on I found an issue with the NE gasket set I was using. The gasket is too big on the outside leaving an unsightly lip that will need to be carefully cut off with a scalpel, the inside of the gasket matches the castings correctly. Not good enough really and involves extra work, I am hoping that the other gaskets are okay and this was just a single gasket problem.

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« Last Edit: March 24, 2019, 10:07:51 AM by royhall »
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline royhall

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #58 on: March 24, 2019, 11:57:14 AM »
I went to refit the grease nipple to the chain case cover and found that the thread had a butchered repair. It had been redrilled at some point and it was way off the correct angle. As the nipple was drilled at 6mm I obtained a stainless nipple with an oversized 8mm thread and prepared to re-drill the cover.

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It's a very awkward piece to hold securely without damaging the paint, so what I did was screw it to the top of the workbench with a couple of wood screws. I found a drill that would fit snugly down the grease hole to gauge the correct angle to drill it at.

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I then carefully drilled and tapped it to 8mm and fitted the new nipple with some thread lock.

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The clutch lifter mechanism, like the neutral switch, is also in direct line of all the crud from the drive chain. Fortunately Honda fitted a good body seal to the back of the mechanism to keep it out. So after a good clean and check of the lifter it was packed with new clean grease and then a new seal fitted, and also a few pumps with the grease gun to completely fill the lubrication passages. The cover was then re-fitted to the engine.

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There is a vital bracket on the rear of the engine that holds the stator cable in place. It is used to hold the cable after the neutral switch to stop it contacting the drive chain. This was missing on the bike when I got it but I managed to find one on eBay in a bag of random bits. The bag also contained a missing clip for under the engine that holds the starter cable in place so was well worth the £12 I paid for it. The clips were pretty rusty so a member on here (wont name them as they will get mobbed with requests) kindly replated them for me. As I say, a small part but vital to the reliability of the machine.

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« Last Edit: March 24, 2019, 11:59:12 AM by royhall »
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline royhall

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Re: 1967 CB450K0 Black Bomber Rebuild - By Royhall
« Reply #59 on: March 24, 2019, 12:14:39 PM »
I mentioned earlier that the alternator cover had a hole in it that I was going to get welded and possibly chrome ceramic coated as new ones were all gone. Well what a surprise when one popped up on eBay being sold on behalf of a forum member. It was a bit expensive but I grabbed it anyway, at least I don't need to repair the old one so shame that I had already had it welded. As it had been sitting around for 50 years the coating on it had gone in places so I shall send it out for polishing later on along with all the other chroming and polishing.

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The clutch cover and centrifugal oil filter cover were then fitted. It now became clear that the gasket problem was going to be all of them, so any other gaskets that are required I shall check out and get genuine Honda items as required. I will trim these two but no more, it just isn't worth the effort for a few extra gaskets. The oil filter cover is looking a little battered and bruised but I am going to leave it. A little bit of patina on a 50 years old bike can't do any harm.

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I'm sorry NE but these gaskets are a mess, what does it take to buy some genuine Honda gaskets and check the ones you make are the same. Not too hard I would have thought. I just wonder how many bikes are out there with these gaskets fitted like this. Never mind I will just have to fit a new scalpel blade and spend 30 minutes trimming them down.

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The next part of the build is to refit the cams and cam chain. As I have not done this type of cam layout before it will be a case of following the manual carefully. I'm sure it will be perfectly simple as Honda appear to have designed this engine with easy assembly in mind. After all you don't want to hold up your production lines with difficult to assemble parts.
« Last Edit: March 24, 2019, 12:18:53 PM by royhall »
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

 

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