Well, it is another crazy referral to my already busy schedule of repairs and restorations, but SOMEBODY has to do it. This time, I received a text message saying that a young guy had purchased a set of 1968 CB175 twins, both with low miles, but had been sitting for almost 30 years. The warehouse photos looked promising, but the reality was less than impressive.
The fragile side covers exploded when they were pried out of the hardened rubber grommets. I had to use a heat gun on the carb bodies to soften up the old gasoline varnish residue. The forks started leaking as soon as the bike was sitting on the side stand. The air filters were all clogged up and in doing research the air filters and covers had a part change in the 4k range, but this bike is 3130. Exact details are difficult to discover with current part number listings. All the control cables were frozen or seized up. The clutch is of particular concern, as it will require draining the oil and diving into the clutch assembly, then scraping the gaskets and reassembling it all.
The front brake cable, which has the front brake light switch embedded, didn’t move an inch until I disconnected it. The brake cams on the brake panel were seized solid. The throttle cable, was of course, frozen due to the slides which were glued into the carb body bores by old gasoline varnish gum. The original tires were badly cracked all the way around on both sides. The left side of the handlebars was bent up and kinked at the bend. When I put an old fork tube on the end to pull it back down, the tubing split open at the bend site. I wrangled with an eBay seller in RI who had a straight and somewhat clean set of OEM handlebars for $70.
The drive chain was rusty, of course, as were all the turn signal stalks and lens units. Rust was the general theme over the entire motorcycle. Both fenders and the tail light bracket were all pitted. The headlight rim screws were very tough to remove, as the ends were rusted where they extended into the headlight shell.
Once the carbs were removed, I pulled the spark plugs for a compression check. Happily, the readings came out in the 130 psi range, which should be good enough to make it run. The carbs were carefully dismantled and bathed in the ultrasonic cleaner for about a half hour. New kits are coming in with the other $400 parts order from 4into1.com I did find a new pair of $100 air filters from DavidSilverSpares.com, here in the US, fortunately.
I spent a half hour removing the front brake panel from the cable and the front wheel, then dismantled it to clean the brake cams and scuff up the asbestos brake shoes, just a bit. I was pleased to see that the inside of the brake drum was still shiny and clean.
The petcock, which was to be replaced with an OEM part, was almost rebuildable, apart from a slotted screw in the retainer face plate instead of a normal cross head screw. The owner had attempted to clean the inside of the fuel tank. We’ll see how well that works out once it is up and running again.
The tubes and rim bands came in ahead of the tires, which were coming from two different locations. Fortunately, the little tires on small bore bikes are generally easy to change with hand tools. The rear tire came in first, so as I extracted the rear wheel assembly, I noticed that the tire was a “Swallow” brand Korean unit in 3.25x18 vs the stock 3.00x18 size. As the wheel was inspected, there were big gouges in the inside of the left chain adjuster, consistent with a thrown drive chain at some point. The bike only had 3800 miles showing and the front tire was definitely the original Yokohama rib showing big cracks in the sidewalls.
The rear wheel sprocket was removed for surface cleaning and the new tire spooned onto the rim. A new drive chain was installed and the whole back end was tidied up as much as possible.
While awaiting the front tire’s arrival, I removed the wheel to clean up the brake cams so the brake action would be restored with a new cable. This left me in a dilemma as the OEM front brake cable has a built-in front brake light switch and these cables are difficult to find and quite expensive. A couple did turn up on eBay, one at $49 and another at $29, but $44 delivered.
The fork seals arrived and with the front wheel in a temporary installed state, I removed it and went about taking the fork legs off. The left side came out easily, but there were ominous signs of rust down inside the chrome sleeve that sits atop the fork slider. Normally these are tapped off with a screw driver around the bottom edge of the sleeve, but this one would have none of that attempt. After spending a half hour trying to tease it off the fork leg, it was apparent that the sleeve was rusted into the fork housing and needed to be replaced. Back to eBay for a set of good-looking forks from a seller in the mid-West for $107 delivered.
The replacement forks arrived, looking very clean, especially at the chrome sleeve junctions. Getting them off without damage will allow for a fork seal replacement and then refilling and installation. Also, the replacement handlebars had a few rust spots, but were miles nicer than what was on the bike as it arrived. All the handlebar switches will be swapped out and then the fresh bars installed with a new set of cables. I was able to track down another of the rare front brake cables with the brake light switch installed for $44, so we’ll keep that function going for these new riders.
I removed all of the headlight wiring connections in order to facilitate the replacement of the bent up handlebars. In the meantime, I laid the bike over on the left side and removed the clutch cover. All the screws had never been disturbed since assembly in 1969, so the use of a 3lb sledge hammer was employed to coax the screws loose. Amazingly, the clutch cover popped off with the gasket completely intact, a rarity in my experience. The clutch plates were a little sticky but didn’t show signs of the kind of “stuck-clutch” feel of the clutch lever when it arrived. A new clutch cable will be installed with the handlebar swap and hopefully the function will return to normal. Happily the inside of the engine looked very clean, owing to its low miles condition.
The new tire arrived along with the cable and handlebars, so a few more hours of work lay ahead.
Winding it down…. 2 weeks later.
So, the handlebar swap took a good bit of time. I had to saw the bent part off in order to retrieve the switch harnesses. The outer sleeves were all crispy and unwilling to move through the inside of the bars easily. Once the switches were installed, then the bars went onto the bike and all the wiring connectors repaired and connected. The cables had to be installed and routed, then adjusted correctly. The last thing was to drain the very dark oil and check the valve clearances and ignition timing.
Of course, spark advancer was rusted to the end of the camshaft and it took flooding the advancer with penetrating oil and my heat gun to get it loosened up for cleaning and adjustment. The points had worn down causing the ignition timing to be quite retarded. The drain plugs on these engines uses a 19mm socket for removal. I had to use a 2ft long extension bar to finally break it loose. Ugly oil splashed out into the drain pan. Like every other screw on this bike, it took an impact driver to loosen each and every one of them. Once the dyno cover was removed, the timing could be set and it was looking like it was about to come alive once again, since 1997!
With the carbs done and installed and new oil and timing checks, it was time to hit the starter button!
Thankfully, it burbled to life quickly and sounded pretty good, apart from the extra exhaust noise coming from the muffler holes. I cleaned up the mirrors and installed them for the first test ride since the last century. Happily, it was feeling like I remembered mine back in 1969, in Puerto Rico! I rode it for about 5 minutes, including a good pull up my test hill and it ran perfectly. It’s still on the ugly side due to all the rust on the chrome and alloy bits, but it seems safe to ride and enjoy once again.
Here, in the end of March, I am juggling repairs on the 1961 CB77, a 1964 CL72 and this first of two CB175s. So, depending upon the parts available, the work load was distributed between the three bikes.
The CL72 finished up first, so will be first out of the shop, followed by the Super Hawk. Once this CB175 is up and running, its stablemate twin will swap out for this current project, no doubt with similar ills. So, no doubt the next CB175K3 will get its own story. Then the fraternal twins will be reunited, both in running condition and ready for the road.
Bill Silver
aka MrHonda
