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1967 CB450K0 Black Bomber Rebuild - By Royhall
royhall:
The rear mudguard was not as simple a fit as I was expecting as the space I had measured to put the extra wiring turned out to be much smaller than I thought. With the mudguard fitted it pushed the wiring right up against the Selenium rectifier that has me concerned about the heat damaging the wiring especially if the rectifier were to fail. As the rectifier is 53 years old there is a fair chance that it could fail so I decided to replace it with a modern unit. It was a fairly simple four wire fix and just a small aluminium bracket to make to carry it. Makes sense really as I have used a later model higher output alternator with a CB250 regulator and electronic ignition so it's already way off standard. May as well go the whole way.
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As you can see from the two pictures it was all pretty tight. Now the rectifier is replaced it has freed up quite a bit of space for the wiring. The wiring is now all accessible from the left hand side and just requires the removal of the left hand side panel and air filter.
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You can see in this shot just how much extra wiring is under the rectifier. Hope all my crimps are good or that would mean removing the rear wheel and mudguard to get a soldering iron in. All the crimps were done with a really good pro crimping tool and passed the pull test at the time, but now I wished I had taken the time to solder them as well. To be fair though I thought the access was going to be much better.
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At this point I fitted the rear wheel and chain, no issues there at all. The chain was sold as a CB450K0 specific item but was about 6 links too long. An easy job to remedy and always better too long than too short. I'm sorry Mr Honda but those mudguards are just massive.
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royhall:
The assembly of the handlebars is a simple affair on this bike. The right hand unit simply contains the starter button and the left hand unit just the lights dimmer and horn button. The unit on the right polished up okay and the starter button tested okay so that went back on and the cable fed through the bars, the left hand unit had a damaged dimmer switch, so as new ones were still available that was replaced. All in all a very simple and quick job.
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The control cables were not as simple a job as I was expecting. I had bought all the cables early on in the build and expected just to take an hour to fit them. The clutch cable was correct but required a lot of research into it's routing as it fouled in many places, I got it right in the end though and once lubricated and adjusted the clutch works really well. The speedo cable turned out to be a K1 part as that's all that was available. It is the correct length and colour but the nut that fixes it to the speedo drive gearbox is longer than the K0 and bottoms out before the cable is tight. The remedy there was to simply hacksaw 6mm off the end of the aluminium nut. Simples. The front brake cable was impossible to source ready made as they are all too long. I was hoping Venhills would remove 110mm off the lever end of one and replace the nipple but they wouldn't do it. Instead they copied the old cable and made a completely new unit, unfortunately they didn't have all the fittings required so had to reuse the bottom adjuster. It's not been re-plated but you cant really see it on the bike when the rubber boot is pulled on.
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As I had already fitted the pattern seat I thought it prudent at this time to try the petrol tank on to see how the fit is between tank and seat. I had no cause for worry as the tank went straight onto it's new mounting rubbers with the aid of a smear of rubber grease and the seat closed with a perfect gap. Well pleased, and first time in years that the bike looks like a Black Bomber again.
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I have jumped ahead a bit with the pictures as I forgot to to take snaps at the time. Next job is fitting the carbs and air filters that from the above picture you can see are already fitted. A real Blue Peter car crash. I could have cropped the picture but to be honest I cant be bothered.
royhall:
Next up was the carbs. I sent the original carbs off to the guy I always use for refurbishment, Matt Harper (sales@harpers-ultrasonic.com). I used to do them myself years ago but these days the old eyesight isn't what it was, nor is the patience with all the stuck tiny screws. After stripping and checking the carbs they were declared scrap as they were simply worn out. Taking advice from Matt plus a bit of research online, I decided to go with a set of CB500T carbs. These were restored with new 450 jets and needles (supplied by Ash) and the accelerator pumps blocked off as the pump diaphragms are not available. Matt was of the opinion that the pumps would deliver too much fuel to a 450 and flood it. Time will tell if he was correct.
They were an easy fit with new genuine rubbers and clamps. The pattern air filters also fitted okay as I had previously fitted them and got around the usual pattern part fitment issues. As you can see, the filter top mounting bracket is in the wrong place so required slotting to get the bolt in.
The weird spring steel choke connector took a bit of sorting out until I realised that the 450 and 500 items are different. Fortunately I had a 500 link sent with the carbs, so job done.
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royhall:
Next up is the replica silencers that came from CMS via DSS with the proud boast that they are made to exacting Japanese standards. Well they don't fit. What a surprise pattern parts that don't fit who'd have thought. The problem is the standard Bomber mounting brackets don't fit, on ringing DSS they informed me I needed K1 brackets. After wasting a further £50 on K1 brackets I discovered that they don't fit either. Very annoying, I really wish these companies would actually test fit these pattern parts then they would know that they are wrong. It appears that there is nothing wrong with the silencers themselves it's just a rear bracket issue so I have decided to make some brackets myself. I could have used mild steel and painted them but instead decided to make life hard and use 3mm stainless.
I have started to make the brackets but have come to a dead stop. The problem is that I don't have a right hand downpipe at the moment as it's still at the chromers. So I have fitted the left pipe and started the rear brackets but need the right pipe fitted to get height and length alignment so all stop on that job. I am also waiting for the headlamp rim from the chromers so I can finish the wiring.
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Once I get the correct positions I can mark the mounting hole and drill it through. This stainless is a real pig to drill and cut. Once the drilling is done I can mark out a triangular shape between the holes and cut them out properly. Then deburr and chamfer and polish them to a nice finish.
So until the chromer comes through that's as far as the project can go. This is where its up to now. The last picture makes the seat look out of line but it's actually not closed onto the clamp. It fits perfectly when it's fully down. The seat itself is the lipped model that shouldn't really be fitted to this bike. I chose it because I like the blended to the tank look that it gives and it also protects the tanks paintwork as the bike will be getting some use. When it comes to selling it I am having the original seat refurbished so it can go with it, or be fitted before sale. The original flat seat and tall tank join reminds me of the 1970's nut crusher MZ250, not a good look but that's just personal preference.
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Moorey:
Stainless requires good quality sharp drill bits a little Trefolex and a slow drill speed and you should be OK. It work hardens very rapidly.
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