Rescued from a shed – 1973 Honda CB125

Sometime after I bought my 1980 Honda CB900 (2005), I was approached by Tom Trimingham, a fellow member of the Bermuda Classic Bike Club, to ask if I would be interested in buying his 1973 Honda CB125 twin. I didn’t have any disposable cash at the time, so I declined. But, whenever we met at club events, Tom would remind me that he still had the bike in his shed (along with a second bike that was in parts).

In July 2007, I relented and went to Tom’s shed to take a look at the bike. Tucked away in a corner, it was totally covered in saw-dust from Tom’s woodworking hobby. It had been relegated to the shed ten years earlier due to some issues and had sat there since, untouched. It didn’t look pretty but it was a complete bike and there were many boxes of parts that were being offered with it. Tom wanted to clear out the shed to make space for his other hobbies. We negotiated a price and I arranged to have everything trucked to my home.

The bike was a CB125 K5 twin but, somewhere along its journey, it had been fitted with a high-level scrambler-type exhaust instead of twin exhausts. I think the exhaust and its handlebars were from a Honda CL125. Not stock, but I liked the look that the exhaust gave the bike. The most obvious issues with the bike were a rusty fuel tank (inside and out) and a torn seat. As time progressed, I would learn that it had several other issues.

 

The stash of parts that came with the bike was sizeable. In addition to another frame, forks and engine, there were boxes full of stuff. The contents of the boxes ranged from loose nuts and bolts to new old stock (NOS) items, still in their packaging. When the C.E. Young motorcycle shop was closing, Tom had gone down there and bought most of the NOS parts for Honda CBs at a bargain price.

 

The best course of action for a bike like this, having sat for ten years, would have been to get everything working first, before addressing cosmetic issues. However, the fuel tank was full of rust and would need to be cleaned out and sealed before I could put fuel in it. So, I decided to do things a little backwards. After some research, I decided to get the inside of the tank cleaned and coated with phenol novolak epoxy. The epoxy treatment leaves a smooth glass-like coating that won’t break down, unlike some of those self-sealing kits on the market. I found a company in New York, called Empire GP, that was able to clean and coat the tank and also paint the exterior. So, I decided to get the tank and side panels repainted, in addition to the tank sealing. I chose a classic stock design for the tank and decided to have them painted in Honda’s ‘Candy Gold Custom’. Several of the NOS parts that I had were in that colour, so I shipped one of them with the tank and panels so that the paint shop could colour-match it. I was very impressed with the paintwork, which completely changed the look of the bike.

 

Whilst the tank and side panels were away in New York, I spent some time on the seat. The cover was torn in a couple of places so I needed to recover it. As the cover was going to be removed, I decided to improve the comfort level of the seat by adding a polymer pad insert from Carolina Butt Buffer.

Due to the smaller size of the seat on a CB125, I ordered the Butt Buffer ‘size P’ insert, which is primarily intended for the pillion section of larger seats. The polymer insert fits the front of the CB125 seat perfectly.

I marked out the location for the pad and then used a Rotozip to cut along the outline and to cut the removable section into cubes. A sharp knife was then used to cut out a section for the polymer insert. I used a hand sander to level out the cut-out section.

The polymer insert was placed into the hollowed-out section and I used some rubber cement to secure it and a piece of thin foam to cover it. A local upholstery shop custom made a new cover for the seat.

 

By October 2007, three months after I acquired it, the bike was at least looking much better. It had been cleaned up, the fuel tank was cleaned and sealed, the tank and side panels were repainted and the seat repaired. New tyres were also fitted.

 

I found some electrical issues that needed attention. Of course, after sitting unused for 10 years the bike needed a new battery. Once the battery was fitted I realised that there was no horn fitted.  I was able to purchase a 6-volt horn from a local dealer and I then wired it up and connected it to the harness.

I also discovered that the rear light didn’t work. As the stop light was working, I assumed that it was simply a defective bulb, but the problem persisted after new bulbs were bought and fitted.  I discovered that the rear light worked when the ignition switch was turned to the ‘park’ position but not when turned to the ‘on’ position. Unable to find any loose connections in the switch, I bought a new ignition switch and that fixed the problem.

 

Having sat for 10 years without being started, and with 10 year-old fuel in the tank, it was obvious that the carbs would need some attention.  I removed the carbs from the bike and took them to my friends at Howard’s Cycles for a clean up.

The carbs were given a clean up and the engine was checked over.  Once it was returned to me the engine was running for the first time in 10 years.  After some adjustments to the carbs, the engine was ticking over nicely but the bike didn’t have full power when out riding. Here began what seemed like an endless search to find the culprit.

Despite the recent work, the carbs leaked fuel whenever the bike was not running. To rule out the carbs as the source of the poor performance, I acquired a set of NOS carbs and fitted those. No more fuel leaks but the bike still wasn’t running correctly (except at idle).

 

The bike went back to Howard’s Cycles and the engine was pulled out and put on the bench. A new block was fitted, piston cleaned up and new piston rings fitted. Valves were also overhauled before the engine went back onto the bike.

 

I was able to get the bike licensed by December 2007. It was on the road, but it still only had partial power. I had a pretty bike but I couldn’t ride it very far, or very fast, despite the attention of a few mechanics. This state of affairs lasted for over four years. At least I had other bikes to ride!

Along the way, I managed to find a NOS air filter for the bike online. There aren’t many about!

 

I don’t know why none of us thought of it earlier, but in 2012 whilst a mechanic was working on the bike, trying to chase the problem, he realised that the exhaust was clogged up with carbon deposits. Enough gases could escape when the engine was idling, but when more fuel was being burned, the clogged exhaust system couldn’t vent the gases effectively and the engine bogged or died. I removed the exhaust system and tried multiple times to clear it out using industrial strength degreaser. I was able to get a lot of carbon deposits out, but not enough. I found a used exhaust system on e-bay for a Honda CL350 and had the muffler from that welded onto the header pipes for my bike. The muffler wasn’t as attractive as the old one, but it was allowing the engine to run better than it had previously during my ownership.

 

I could finally get to enjoy the bike a bit more but, by 2013, I was heavily into the preparation stage for my Land Rover. So, the little Honda was sold to help pay for my 2014 adventure. It was a frustrating few years, but at least I was able to rescue it from Tom’s shed and pass it on to a new owner in a much better condition.

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