My 1978 Honda Motorcycle Rebuild

Two years ago I decided that I wanted to learn how to ride a motorcycle as a fun challenge for myself. After doing lots of studying and passing the M1 and M2 license tests, I realized that if I ever want to actually ride on the road, and not just in a parking lot while I was learning, my next step would be to find my first motorcycle. I ended up buying a motorcycle off of a friend for $100. This bike was from the 70’s and did not include any form of paperwork whatsoever (more on that later).

Finding my Bike

After seeing the few photos of the bike (shown above), I decided that it wouldn’t be a huge investment even if it never ran so I decided to buy it before ever seeing the motorcycle in person. When it came time to pick up the bike, I was over-the-moon excited just for the fact that I officially owned my first motorcycle, no matter what condition it was in! (Spoiler alert, the condition was rough). I brought the bike to our garage and spent several days cleaning it up as much as possible with rags, cleaner and steel wool. Normally I would never suggest steel wool on a motorcycle, but this one had a sever case of rust everywhere so it couldn’t hurt.

Starting the Teardown

Next up, I took off all of the least daunting pieces and one-by-one cleaned, labeled and polished them up as best as possible. This made it very easy to know which parts would need to be replaced eventually. I also downloaded a pdf version of the original owners manual for the bike as well as a complete shop guide to use as reference.

Dealing with all the Carbs

One of the areas that I knew I would eventually need to clear out on the bike was the carburetors. With the bike sitting outside for so many years without ever running, I thought that if there was even a chance the engine would run again, I would need to take the carbs off the bike and clean them out well. This was also around the point where I couldn’t understand why the owners manual didn’t match my bike exactly, even though I knew the bike was a Honda CB400 from 1978. It turns out, one of the previous owners must have swapped out the original 400cc engine for a similar 450cc engine from a different bike This wasn’t necessarily a bad thing as it gave the bike a little more power (although the updated engine didn’t include a kickstart like the original would have, only electric).

After removing the carbs off of the bike, I noticed multiple areas where the gunk inside them was hindering how they function, no wonder the bike never stood a chance of starting up before this!

The Engine’s First Chance

With the carbs cleaned out and put all back together, it was time to see if the motorcycle engine would even turn over, or if it was seized and I was out of options.

To my surprise, after a few tries the Honda started up! Keep in mind it ran very rough only if I kept giving it lots of gas. Idling at the moment was really not an option. This was an exciting point for me, because it meant my time and effort was not all for nothing. I quickly moved on to other areas of the bike now that I knew the engine would be ok with some more tweaking.

Repairing the Chain

Initially, I had assumed that I would need to buy a new chain for the bike because the current chain was completely seized in-between some of the links and had lots of rust across the board. I did lots of research online and after taking the advice of many people online, I submerged the chain in oil for multiple days, individually loosened up each link by hand gently using pliers, and cleared off the rust with steel wool and a wire brush on my drill. Who would have thought that the chain ended up functioning great once I put the work in!

Here Comes the Paint!

One of the most fun parts of working on the bike was when it came time to paint. Even though the ownership described the bike as blue, it had been painted glossy black at some point before I took ownership of it. I decided to keep as much chrome on the bike as possible, and everything else (besides the gas tank) I spray painted matte black from a aerosol can.

With lots of painters tape masking all the different areas, and even more patience, I was able to bring some life back to the bike and freshen up it’s look.

Somewhere to Sit

One of my last hurdles was what to do about the motorcycle’s seat. The original seat had been very roughly covered in generic materials years before, and since then it had been worn right through with a combination of riding use and being left outdoors.

My original thought was to purchase an inexpensive café racer-style seat from Ebay and that would be the end of it. But once I put the new seat on the bike I realize how ridiculously small it looked unless I made major alterations to the bike frame which I didn’t want to do. I ended up deciding to take apart the original seat.

I remove the worn material and original foam from the metal base of the seat to find that it had been heavily rusting out. As I was about to through out the old seat, I decided to see what the metal looked like underneath all of the rust, and it turned out to be salvageable! I spent many hours brushing away piles of rust with a steel brush attached to my drill. I then had my Dad’s help to spot weld a couple areas where the seat frame had been cracked from lots of use.

By the time the seat was completed, I had cleaned off all of the rust and recovered it with a proper leather upholstery from Saddleman. The seat turned out much better than my original option from Ebay ever could.

Showing it’s Name

All that was left to do on the bike now was to add the small details like the missing Honda emblems to the gas tank and mirrors because they were the one thing missing when I had bought the bike for whatever reason.

Safety First!

My very last step was to buy brand new tires for the bike. Even though the tires that the motorcycle came with looked in good condition, they were made so long ago that the rubber compounds in them would not have been very reliable. The tires were a few hundred dollars, which hurt considering they were triple the cost of my actual motorcycle, but the wheels are an area I did not want to cheap out on!

The Final Result

Before I bought the motorcycle from my friend, it had been abandoned and left out in the rain and elements for who knows how many years. After months of working to get the bike back up and running and after eight trips to Service Ontario, yes eight, I finally had all the paperwork and everything sorted out so that I could now officially call this Honda CB400 bike my own.

This motorcycle is now my daily commuter vehicle during the nice months and a great hobby for any weekend! It may have been a lot of work and stress, but at the end of the day, I learned a lot about motorcycles function and I get the satisfaction of riding to work each day on my own DIY project.