Author Topic: CB350F - Slow Time Restoration  (Read 11700 times)

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Offline ozm29c

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CB350F - Slow Time Restoration
« on: February 21, 2020, 11:36:34 PM »
John W. here. Recently I picked up the remains of three CB350F's. There are enough 'Core' parts to build one bike, possibly two. I have had a chance to dismantle the bikes (or whats left of them) to look at the frames amongst other things. The first frame I have is in excellent condition but unfortunately the VIN tag is gone. The second frame is in repairable condition but it is corroded and damaged in way of the rear footpeg supports and the last #3 frame I have, well I will let the photo do the talking. I have done a lot of metal fabrication work on other projects but the corrosion in this #3 frame looks terminal. Having said that, the rear footpeg frame supports on this .#3 frame are in excellent condition and would be good donors to repair the #2 frame. Do I scrap and cannabilise the #3 frame (someone out there could make use of the remaining sections of this frame for donor parts) and repair the damaged foot frame supports on #2 using donmor parts. Look forward to the thoughts of Learned Honda Scholars. Cheers 
« Last Edit: April 13, 2022, 05:55:35 PM by ozm29c »

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #1 on: April 13, 2022, 06:07:55 PM »
Fellows,
It's been quite a while since I updated this thread hence the subject name change. I am still slowly plugging away with this restoration so I will update where I am at. I made the decision to cannibalise the extremely corroded frame and removed the rear foot peg/exhaust outriggers (for want of a better word) in order to transplant them onto my keeper frame. The original foot peg/exhaust outriggers had both corroded internally and were damaged. The attached photos better describe the end product. I did take the opportunity to bead blast and preserve the inside surfaces of the foot peg/exhaust outrigger. The large chunk of Aluminium in the photos is just a spacer piece I made to hold the outriggers in position for welding. The frame is now ready for abrasive blasting and painting.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #2 on: April 13, 2022, 06:17:06 PM »
The next problem to deal with was to repair a damaged section of the engine casing. Fortunately I had a donor piece of engine casing to work with. I made a special little holding jig to correctly position the donor piece for welding. I don't have the equipment to weld Aluminium so this was a job sent out to a company that specialises in welding aircraft components. Fortunately there was no charge as the job was put through by a friend who works in the aviation industry. I was very pleased with the repair. Once I got the engine casing back, it was just a matter of dressing down the welds.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #3 on: April 13, 2022, 06:38:23 PM »
Next job on the list was to repair a damaged thread in the engine casing and then prepare the casing for bead blasting and painting. I am not a fan of bead blasting/vapour blasting machined surfaces so I went to the extra trouble of plugging all of the holes in the casings and then making protective covers out of Perspex to protect the machined surfaces. The covers worked well. After bead blasting, I applied a coat of etch primer followed by a coat of Dupli-Colour DE1615 Aluminium engine enamel. I repeated the process for the other engine casing. One small job was then ticked off the list. First photo shows the thread being repaired, nothing special there.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #4 on: April 13, 2022, 06:40:36 PM »
Photos of the perspex covers in place prior to bead blasting

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #5 on: April 13, 2022, 06:41:53 PM »
Engine casings in etch primer.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #6 on: April 13, 2022, 06:42:55 PM »
The engine casings look resplendent in Silver.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #7 on: April 13, 2022, 07:30:59 PM »
I decided to work on the mudguard/fender that came with the bike. The rear mudguard/fender chrome looked salvageable but the underside had a good degree of corrosion. I decided to first try and restore the chrome finish. Using a lot of elbow grease I was more than happy how the chrome finish was restored. Not perfect but close to. I then taped up the chrome to protect it from bead blasting and in view of how much corrosion was there, the underside of the mudguard/fender came up OK following a coat of etch primer and Dupli-colour Silver. Not OEM I know but a practical way to save this original part. 

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #8 on: April 13, 2022, 08:13:48 PM »
The air box showed the usual signs of corrosion. I had to remove the hinge bracket to deal with some corrosion between the sheet metal. A bead blast, etch prime and coat of single pack epoxy paint has restored this part ready for use.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #9 on: April 13, 2022, 08:22:06 PM »
The steering lock and lock retaining cover could have been considered past entities  :) I took the steering lock to a master locksmith and he made a set of keys for the original steering lock. Not bad value for $26. The plastic retaining cover was unserviceable but I did manage to salvage the metal hardware from it. I machined a new cover out of mild steel stock and after painting I retrofitted the original metal hardware. Again not concourse but still very functional. Saved a few $$$$$ not having to buy a repo replacement.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #10 on: April 13, 2022, 08:28:46 PM »
The handlebar switches were in a very sorry state but I decided to try and repair them after seeing the price for NOS originals not to mention the questionable quality of the aftermarket versions. The first task was to strip them down, bead blast them and then take stock of what repairs were needed.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #11 on: April 13, 2022, 08:39:42 PM »
The handlebar retaining pin was missing from the indicator switch. I machined a replacement stainless steel pin and then tapped an M6 thread in the switch housing. A little bit of loctite before assembly and that job was done. Next the thread that supports the clutch cable adjuster was all but corroded away. After carefully drilling and tapping an oversize thread in the switch casing I fitted a machined insert that I secured using a 2 pack epoxy glue. I then set the housing up in a milling machine and carefully machined a new slot. So far so good.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #12 on: April 13, 2022, 08:50:29 PM »
I then bead blasted, etch primed and painted the switch housings in black single pack epoxy. I also bead blasted and painted this internal metal switch hardware. Painting the red lettering in the switch housings was easier than I had anticipated and the end result was great. I also machined a new clutch lever hinge pin. I forgot to mention that one of the small die cast switch housing retainers for the horn button contact had disappeared thanks to corrosion. I machined a replacement retainer and was happy with the result.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #13 on: April 13, 2022, 09:03:21 PM »
The time came to assemble the switches. All went well but I was missing the knob to actuate the light switch. I have just started to experiment with 3D printing so I measured and drew a knob in 3D first and then printed it out. The replacement knob turned out OK in view that I doubt if you could buy an original replacement. Last but not least I have replaced the plastic conduit that protects the wiring. It was certainly a character building job threading the wires back through the original handlebars. There are still a few more jobs to be done to finish the handlebar switches but I am really happy how they have turned out so far.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #14 on: April 13, 2022, 09:06:53 PM »
Photos of the 3D knob

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #15 on: April 13, 2022, 09:12:52 PM »
3D light switch drawing and handlebar to date

Offline carnivorous chicken

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Re: CB350F - Slow Time Restoration
« Reply #16 on: April 14, 2022, 12:10:29 PM »
great stuff

Offline Robbo

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Re: CB350F - Slow Time Restoration
« Reply #17 on: April 14, 2022, 02:45:59 PM »
Wow…fantastic work


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1973 CB350 Four, 1975 CB550K

Offline WhyNot2

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Re: CB350F - Slow Time Restoration
« Reply #18 on: April 30, 2022, 04:10:40 AM »
wow...........nice work.
If it ain't raining, I'm riding.....~~{iii}?~~prost

If it sounds like I know what I'm talking about, it's because I cut and pasted from someone else.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #19 on: May 02, 2022, 06:22:54 PM »
Thanks all, I appreciate your compliments. Next sub-project on the agenda is to build a good fuel tank using the tank that came with the bike and a donor tank. When I removed all of the bondo from my tank that came with the bike, I found that a major repair had been done previously on the near side front of the tank. The PO had accessed the inside tank area by cutting an access hole on the inner side of the tank. Unfortunately the tank is now not 'true' after the repairs. The attached photos better show what I am alluding to. The donor tank (blue tank in photos) has some large dents on the upper surface but it has a great lower pan. If I can't repair the donor tank then I will unzip the bottom pan from the donor tank and graft it onto the other tank (grey tank in photos). Anyway a plan is a basis for change so stay tuned for future updates on this tank repair.   

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #20 on: May 23, 2022, 09:31:03 PM »
More photos of the two halves coming together. The lower plate from the donor tank and the upper tank shell from my original tank. I am taking the opportunity to panel beat the upper tank shell surface as best as I possibly can before joining the two halves together.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #21 on: October 23, 2022, 09:10:33 PM »
Moving on from my last post, I have now completed the repairs to the fuel tank. I spent a good deal of time tapping out the myriad of small dents. I did find that a sheet metal shrinking disc works wonders. As I had run out of Argon gas for my TIG welder I just used my MIG welder with 0.8mm wire to rejoin the two fuel tank halves. Some delicate work with my angle grinder delivered an acceptable finish on the weld seams.
Not to OEM standard but I am more that happy with the finish.

Offline newday777

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Re: CB350F - Slow Time Restoration
« Reply #22 on: October 23, 2022, 11:55:23 PM »
That tank repair looks fantastic! We'll done.
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline WhyNot2

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Re: CB350F - Slow Time Restoration
« Reply #23 on: October 24, 2022, 05:18:09 AM »
Wow.......I have a few tanks that need that treatment.........Can I send them your way?

That is some absolute wonderful work......!!!!!!!
If it ain't raining, I'm riding.....~~{iii}?~~prost

If it sounds like I know what I'm talking about, it's because I cut and pasted from someone else.

Offline ozm29c

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Re: CB350F - Slow Time Restoration
« Reply #24 on: January 02, 2023, 07:37:46 PM »
My replacement Frame/VIN tag arrived in time for Christmas. Not quite an OEM finish as the background is a different colour and the Frame/VIN numbers are not inverse stampings but hey, it will be fine for my restoration and I still have the original if needed in the future. Vendor can be found here; https://www.ebay.com.au/itm/153050695190?mkevt=1&mkpid=0...