Author Topic: CB350F - Slow Time Restoration (Read 5770 times)

ozm29c · « **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

ozm29c · « **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.

ozm29c · « **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.

ozm29c · « **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.

ozm29c · « **Reply #4 on:** April 13, 2022, 06:40:36 pm »

Photos of the perspex covers in place prior to bead blasting

ozm29c · « **Reply #5 on:** April 13, 2022, 06:41:53 pm »

Engine casings in etch primer.

ozm29c · « **Reply #6 on:** April 13, 2022, 06:42:55 pm »

The engine casings look resplendent in Silver.

ozm29c · « **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.

ozm29c · « **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.

ozm29c · « **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.

ozm29c · « **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.

ozm29c · « **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.

ozm29c · « **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.

ozm29c · « **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.

ozm29c · « **Reply #14 on:** April 13, 2022, 09:06:53 pm »

Photos of the 3D knob

ozm29c · « **Reply #15 on:** April 13, 2022, 09:12:52 pm »

3D light switch drawing and handlebar to date

carnivorous chicken · « **Reply #16 on:** April 14, 2022, 12:10:29 pm »

great stuff

Robbo · « **Reply #17 on:** April 14, 2022, 02:45:59 pm »

Wow…fantastic work

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WhyNot2 · « **Reply #18 on:** April 30, 2022, 04:10:40 am »

wow...........nice work.

ozm29c · « **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.

ozm29c · « **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.

ozm29c · « **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.

newday777 · « **Reply #22 on:** October 23, 2022, 11:55:23 pm »

That tank repair looks fantastic! We'll done.

WhyNot2 · « **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......!!!!!!!

ozm29c · « **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...

ozm29c · « **Reply #25 on:** January 02, 2023, 07:43:50 pm »

I have almost finished repairing the rear indicator lamp support brackets. Yes I know they can be purchased new but it's a challenge to repair the old ones. The countersinks for the retainer screws have been elongated over time so I have replaced the damaged section. Photos tell the story. When done, they are off to the platers. Last photo shows repaired compared to as found.

RAFster122s · « **Reply #26 on:** January 03, 2023, 01:36:17 am »

That’s some very nice work. You have more than a few skills in your quiver.

bek1966 · « **Reply #27 on:** January 03, 2023, 07:55:53 am »

Brilliant work John. The 350 Fours are fantastic little bikes and well worth the effort to bring them back to service. Good on you for your efforts to return at least two more to the road. Thanks for sharing!

Brad

ozm29c · « **Reply #28 on:** February 23, 2023, 04:47:09 pm »

Another one of those time consuming restoration jobs completed. This time cleaning the conrods. When I removed the conrods from the engine, they were covered in baked on scaly oil residue and some corrosion for added measure. I machined an aluminium adaptor to protect the ground surfaces from glass bead blasting. I also buffed the thrust faces on a nylon mesh/aluminium oxide grinding wheel. Without going into too much extra detail, the pictures better tell the story. I also had to restamp the rod grade (#3 for all rods) and a letter identifier for each rod.

RAFster122s · « **Reply #29 on:** February 23, 2023, 10:22:50 pm »

This 350 is a priceless rebuild. What is , or was, your occupation? You clearly have superior machinist and fabrication skills. Most will never have a clue the lengths that you have taken to bring this one back.

Few would invest the time and money to bring one back using original parts you rebuilt, instead replacing everything.
This is akin to restoration work on very rare motors and vehicles that occurs when you have no option but to do the costly and time consuming refresh/rebuild/remanufacturing you are undertaking.
WWII aircraft see this kind of work routinely.

Thank you for sharing with us the insight and glimpses into the skills and rebuild you are doing.

David

ozm29c · « **Reply #30 on:** February 24, 2023, 07:02:26 pm »

David, thanks for the BZ. It took 3 and 1/2 years of delicate negotiations to finally purchase this project bike along with what was left of two donor bikes. I must admit that I do enjoy the challenge of restoring this bike. I am a Fitter/Machinist by trade and learnt my skills by serving 20 years in the Navy. I must admit that this is my first bike restoration. My last restoration was a Studebaker Weasel that took 23 years (not full time though

) to complete. Photo attached. Like most restorers, you can see where my strengths lie but having said that I have a friend who is a professional panel beater/spray painter to do the painting. Painting is not one of my strong points. Cheers.

ozm29c · « **Reply #31 on:** April 19, 2023, 09:49:53 pm »

Another small step, my fuel tank has been lined and is now ready for paint. In view that this tank has been through some major metal surgery and I used a MIG welder to rejoin the tank halves, there were only two small pin holes found.

ozm29c · « **Reply #32 on:** June 28, 2023, 10:19:39 pm »

A small report today. Slow but steady progress working on the carburettors. The expensive carburettor repair kit that I chose to purchase off Ebay had the all important replacement linkage ball straps and felt washers however the fuel bowl gaskets were incorrect. A lot of time was wasted sourcing the correct replacement fuel bowl gaskets, one of the down sides of working through Ebay. I also found that one of the plastic inter-carb connector pipes was missing and the remaining one was beyond repair as the plastic had aged. I machined two new aluminium replacements. Drawing attached. The OEM jets came up a treat after some cleaning and a soaking in some CLR. I did find that the idle jets were missing from this Carby set

? so I will have to source a replacement set. As you can see in the last photo, I still have a way to go to get the carburettors back together.

ozm29c · « **Reply #33 on:** July 06, 2023, 04:33:12 pm »

This is where time can get away on you when restoring a CB350F. Over the last few days I have been working on the Carburettor linkage holders. Unfortunately the Carburettor set that I found had been cannibalised for the link ball stops, for want of a better word. I have machined a new set out of brass. Also I finally have a set of the rubber covers for the linkage holders. Now its time to put this together.

newday777 · « **Reply #34 on:** September 05, 2023, 03:24:45 am »

Quote from: ozm29c 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.

How did you unzip the seams? Someone else was asking if anyone had done a tank repair.

Any further progress reports on the bike?

ozm29c · « **Reply #35 on:** September 05, 2023, 02:54:25 pm »

Fortunately the tank seams are not spot or machine welded seams . It was just a case of lightly running along the top of the seam join with a flapper disc in my angle grinder to just remove enough of the weld and expose the join. Hopefully the attached photo will give you an idea how I did it.
As for progress I have been bogged down with the rebuild of my carburettors. The last piece of the puzzle arrived in the post last Friday. Thanks to advice from this forum I was able to track down a set of the elusive link rod dust seals. They came out of Japan and cost a small fortune. Here is the link to my report;
http://forums.sohc4.net/index.php?topic=193163.new;topicseen#new
Once the carbs are together I will be moving on to the gauges.

ozm29c · « **Reply #36 on:** September 07, 2023, 09:18:42 pm »

My Carburettor rebuild is done for now. Thanks to the generosity of some SOHC members I managed to find the last hard to find items, believe it or not, the simple hose clamps. I did a static adjustment of the carburettor slides with a dial indicator which will be more acceptable for the first engine start. Photos attached. Now onto the Gauges.

RAFster122s · « **Reply #37 on:** September 08, 2023, 04:26:00 am »

Quote from: ozm29c 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...

BTW, it is not uncommon for black to weather into the odd brown of your original VIN plate.
Most mess up with the rivets they use to reattach the plates as they are not like the stock rivet pins and a skilled inspector will easily see more modern substitutes people try to pass off for VIN plate swaps people try to do.

ozm29c · « **Reply #38 on:** November 09, 2023, 07:31:52 pm »

Just a short update. Received a pile of goodies back from the Electroplater, Winkler Chrome Plating over in Lismore NSW. Of note, Mark did wonders bringing my OEM front mudguard/fender back from the dead. Of course he relieved me of a lot of cash to restore this part but in the end it was still cheaper than importing a repo from overseas.

News:

Author Topic: CB350F - Slow Time Restoration (Read 5770 times)