How to Turn a Junkyard Bike Into Collector's Bike

HI everyone,

In this instructable I'll show you how I turned a junkyard bike that was left in a backyard for about 30 years into a new, beautiful bike that'll be entered in a motorcycle contest and of course, giving you tips and how to's along the way ;)

Many people may think that it is kinda crazy to get a bike that is not running, and did not for at least 30 years, has no brakes and that is covered with dirt and corrosion, but sometimes, it can be saved without too much effort!

Ideally, it is better to have some mechanical knowledge for this kind of restoration, but you can actually lot a lear along the way, that's how I learned everything :)

The idea behind this instructable is that by telling you what I did to restore that bike, it'll give you a checklist of about everything you need to do, or check, if you want to restore a bike and make it rideable again! I may not go into all the details of every steps, but I will tell you what you need to do, and you can also find more details in my other instructables ;)

One says an image is worth a thousand words right? so I guess a video is worth billions of words :)

I like to record me working on my motorcycle projects and for this one, I recorded every single step to make a huge timelapse of the rebuild and transformation of the bike, so there you go, you'll be able to see in this video every step I'll describe in this Instructable ;)

PS: if anyone is wondering, the white smoke coming out of the exhaust at the end is normal. It is because it is the first start of the motorcycle after rebuild and it still has to evacuate some humidity from the cylinder and the fogging oil I used into the cylinder ;)

Before detailing each step of my Instructable, I wanted to tell you guys what you need to know in order to make a junkyard motorcycle run again: what do you absolutely need to check? how much does it cost? how "easy" is it?

If you find yourself with a junkyard bike, or a bike that hasn't run in many years, there are some key components that you'll absolutely need to go through in order to be able to ride it again:

- Engine: Without an engine, you can't ride. You'll want to determine if the engine is seized (pistons can't move at all) or fine. If the engine is seized, you'll most likely have to rebuilt it and open it up, if not, you can probably just restart following the step I go through in the upcoming steps of this instructables.

- Final Transmission: the final transmission is what will allow you to transfer the power from the engine to the rear wheels. Most of the motorcycles use chain, some do have shaft drives. If your motorcycle has a chain, best thing will just be to replace it, old chains are often corroded and damaged, and a new one will only cost around $25 to $50

- Wheels & Suspension: this is a crucial part because they are the contact surface of your motorcycle to the road. On old bike that has been stored for decades, you'll have to change the fork oil and seals, it is not difficult to do and pretty cheap, about $10 for the seals and $15 for the new oil. As for the shocks, it is often better to replace them, but once again, you can find new replacement shock for just about any bike for under $100, so less than the price of having the old shocks rebuilt.

For the wheels and tires, most of the time, wheels will likely be fine, except for spoked wheel like on my 350 Four, which will probably be rusty and need to be replaced. Tires however will almost always have to be replaced, remember that a tire lifespan is 6years, even if the bike is not riding during that time (which is actually worse for a tire) because the rubber will harden causing slipping especially in corner. So never try to ride on old tires, always replace them, it is a matter of safety, and most of the time new tires will cost less than $150

- Brakes: Finally, THE most important part on a motorcycle, its brake. On an old bike, it is always better to restore the brake, that is to say change the brake pads (or shoes for a drum brake) and change the brake fluid (it needs to be changed every 2 years because of humidity in it). You'll likely need to rebuild the master cylinder too with new seals, or maybe you'll just want to change it for new one. Brakes pad or shoes will cost around $20 per brake, brake fluid $10, and a master cylinder rebuild kit, or a new universal master cylinder around $50.

On disc brakes, it is also a good idea to replace the old rubber brake lines with new one, stainless steel brake lines are great upgrade and not too expensive.

So, this is the bike I decided to save, the one in which I believed had a lot of potential!

It is a 1973 (I think from the chassis number) Honda CB 350 Four, the smallest one of the Honda CB Four series, it was only produced from 1972 to 1974 so it is not a very common bike.

But what liked about this bike was especially this! having a 350cc 4 cylinder is VERY uncommon, it's not something you see everyday and just a few models of such small 4 cylinder motorcycle were actually massed produced.

The bike condition:

When I got the bike, it was pretty much a wreck, it didn't run for at least 30 years, so the engine needed to be fully inspected and restarted, it had no brakes at all, and overall, was in a terrible condition: corrosion everywhere, the gas tank had a lot of dents everywhere, the forks and shocks had no oil left at all inside them because they were leaking... so everything had to be rebuilt.

The motorcycle also shown many signs of crashs, so I believe a crash may have been the initial reason why this bike has been put away many many years ago. The speedometer had dents, the lower tripple clamp had a broken "turn stopping part" which can only happen in a nasty crash, and many parts were missing, like electrical compoments, brake parts, etc. So I believed people then came to pick up parts on this bike when it was stored.

I could tell that the bike had not been run for a long period of time when I pulled the fuel petcock off the bike and oppened it, well first of all it broke, but inside of it,was a lot of solid dirt!! the gas that was once in the tank sat there for so long it turned into solid chunks of dirt!

So now that I got the bike, it was time to restore it, and my first goal was to make that little engine run again!

Here we are, probably the most exciting part of this restoration: start the engine again. I actually wanted to try to restart an old engine for a very long time, it was a challenge I always wanted to take :)

So, when trying to restart an engine, it is crucial to know what actualy allows an engine to run! what does it need?

Well it is actually pretty simple, it needs:

• Fuel
• Air
• Spark
• Free moving parts (piston, crankshaft, etc.)

Lets start by the "free moving parts", it just means that the engine must not being "seized", aka the piston can move freely inside the cylinder, and others partks like the crankshaft are fine too. When I got the bike, I tried to gently crank it with the kickstarter and immediatly saw that it was not seized and that it could turn easily, so this part was good!

Then, for the fuel and air, those 2 depends on the carburetor, it is the carburetor that will bring the correct fuel/air mixture to the engine, so the first step here was to entirely rebuild the carburetors.

And finally, for the sparks: there are several component needed for a proper spark: spark plugs, plug caps, coils, points, condenser, etc. A single faulty part would cause no spark at all, and those parts are actually pretty cheap, so best thing is just to replace all of them, which I did (except for the coils because I tested them and they were still good).

Now, let's start with the carburetor rebuild:

The 350 Four has 4 carbs, one for each cylinder, and any bike that sat for more than a year or two will need a full carb cleaning, and most likely rebuild too, because old gas tend to turn into "gum" and block the tiny ports. Moreover, old seals and O-ring will harden with time and cause leaks.

For rebuilding the carbs, I started by taking the 3 carbs aparts and down to pieces, removing as much parts as possible for better cleaning, there were a lot of aluminium oxyde inside the carbs, it was crazy!

Then, I had the carbs ultrasonic cleaned, 6 times actually, ultrasonic cleaning is a very effective to clean carburetors. It's the best method I found so far.

Finally, I put the carbs back together using a rebuild kit, that is to say new seals, o-ring, needles, jets, etc.

This alone took me a lot of time, you need to be very careful not to mix parts between the carbs and put them back in the correct order. I'd say that rebuilding the carbs alone probably took me 8 hours.

Let's head back onto the engine:

Okay so now that we have a correct air/fuel supply to the engine, we need a spark!!

So to get a proper spark, I start by removing the old points (aka. contact breakers) and condenser, they were so old the points did not made proper contact and did not allow current to pass through. If you are not familiar with points, it is what was used on old bikes before electronic ignition came around to determine when to trigger the spark on the cylinders. It is directly related to the crankshaft which tell the points were the pistons are in the cylinder.

So after replacing the points, it is crucial to set the ignition timing by turning the crankshaft to certain marks, which indicate certain positions of the pistons, and adjust the points accordingly. It is not a difficult task, you just need to be patient and have a static timing light. I actually made one with a 12v led and 2 alligator clips lol

Now, before even trying to start this engine, it absolutely needed new oil, you can't run an engine that hasn't started in decades, which 30y/o oil. So I drained the old oil and changed the oil filter, then poured in some cheap fresh oil because I only planned to run the engine for 15min on that oil before changing it again! I also added some "Engine clean" oil additive to help remove dirt and debris from the engine.

I then replaced all 4 spark plugs, installed new plugs caps and... we were good to go!!

So.. did it run?? I'd say watch the video and find out ;)

Spoiler alert: It did!!

To make it start again, I hooked up a battery, fuel supply line to the carbs, and starting cranking it!

I eventually restarted, with a TON of SMOKE!! it was crazy!! all the smoke was coming from the "carbon goo" inside the cylinders, the carbon had mixed with humidity and created a kind of goo, which had to be burnt off.

Restarting the engine was a first step... but to be able to ride a bike, you need to be able to sit on it, to transfer the engine's power to the rear wheel, and moreover, to be able able to stop it ^^ as Jeremy Clarkson once said: "Speed has never killed anyone. Suddenly becoming stationary, that's what gets you"

So we need proper suspension, final transmission, tires and, well, brakes!

Let's start with suspension:

The old rear shocks were entirely corroded and spongy, best thing was just to replace them with new ones, and since I planned on making this bike a scrambler, I installed new, slightly longer shock that has compression and rebound adjustments for maximum comfort.

As for the fork, they were out of oil because of the damaged fork oil seals, so I pulled them apart, cleaned everything, changed the oil seals, and poured in fresh 15w oil. I used 15w grade oil because that's "heavier" than the old oil, so the benefits from heavier oil will be stiffer forks, which is always a nice benefit on those old bikes.

Now, the transmission:

The final drive chain is what transfer power from the gearbox to the rear wheel. The old chain was just dead, plain and simple, plus someone, for an unknown reason, had remove the master link clip so the chain could just snap at any minute. So here again, the only option was just to replaced the chain, I also replaced the front sprocket during the process.

How about the tires?

Would it be fine to ride a bike with cracked, hard, old tires and corroded rims and spokes? well, actually, no!!

So I also changed the rims, tires and spokes, aka. I re-laced the wheels. The only parts I kept were the wheel hubs.

Here is a tip: if you want to change your spokes, rim and tire, you actually do not need to bother removing the tire and spokes, which can be pretty hard. You can just cut the spokes lol, you are going to ditch them anyway, this will make you save a lot of time!

Once you have just the wheel hub, you need to re-lace and true the wheel, it was the first time I did this, and looked for tutorials online. It is actually not very difficult to do, and does not require special tools, maybe just a spoke wrench. However, it does requires A LOT of time and patience. So my advice for this is just take your time, don't rush it, even if you are frustrated when truing the wheel, because once you mount the tire back on, it'll be a PITA to have to do everything all over again.

Finally, the brakes!

Now, the most important part! the CB350F has a rear drum brake, and a disc front brake, both of which did not work on my bike.

The rear brake was a pretty easy fix, the missing parts were only the spring & nuts that connect the brake rotor to the brake lever on the wheel, so I just bought new one and connected them back. I also bought new brake shoes, but the old shoes were actually in very good shape! so I just kept the new ones as spares ones.

For the front brake, well all the brake fluid leaked out, so no wonder it didn't work, plus the brake pads were worn out. So, I did not bother trying to rebuild the master cylinder (which was probably the faulty part) but just replaced with a new one, that looked a lot better, master cylinders are pretty cheap nowadays. I also replaced the old brake line that was cracked, with a brand new stainless steel braided brake line, I then installed the new brake pads, poured in new brake fluid, bleed the brake, and VOILA !

Bonus tip : How to bleed brake easily.

Bleeding brake is often seen as an annoying thing, that often requires 2 people. Actually most of the time, bleeding brakes only takes me about 20 min.

What I do is I just pour brake fluid in the master cylinder's reservoir, then, before even trying to bleed the system, I just open the nipple on the caliper then with through a (at least 50cm long) transparent hose, I suck air out, either with a syringe... or my mouth lol, and you'll see the brake fluid level go down in the master cylinder's reservoir. Do this few times, then you can start bleeding the brakes normally, and you'll see that it'll be much faster!

How to bleed brakes? pretty easy: pump the lever with one hand, then press it, with the other end open (for 2 sec) the nipple on the caliper, then close it, and then release the lever. Repeat until no air bubbles comes out and brake lever is very stiff!

When I had the idea of restoring and re purposing this bike, I didn't plan on restoring it as original.

Too many original parts were severely damaged or corroded for this, and those original are extremely expensive, the exhaust system for example, that broke in 2 pieces because of rust, cost $1500 alone!!

Plus, I wanted this bike to be even more "all purpose", to be able to ride on the streets, but also be able to go on dirt roads in the countryside!

So I decided to make this bike a scrambler!!

What is a scrambler? it is basically an old school trail bike, most of the time, they are street bike that are re purposed to ride on both street and dirt roads.

What does your bike needs to be a scrambler? well, first of all, the tires, it needs dual purpose tires with knobs, so you can ride the bike in the dirt. Then it is also a good idea to upgrade the suspension, which I did, and also maximize ground clearance, especially by avoiding "low exhaust". Foam air filters are also a good idea, but for occasional ride in the dirt, well oiled and maintained "K&N style" filters can work too, just make sure to clean and oil them often (on every dirt ride).

So I wanted to re purpose this bike as a scrambler but also make it look really cool! so here is what I did to achieve a new clean look:

I sanded down the frame and re-painted in black, I also painted the wheels hub in black to contrast with the new chrome rims and spoke. Installed enduro tires that are great for both road and dirt. I also painted the fork in black and installed fork boots in order to protect the from dust and give it a cleaner look.

I had the gas tank painted in Red to contrast with the rest of the bike.

I wanted to have a very shinny and clean engine, so I spent a lot of time cleaning the original parts, I actually did not repaint any of those!! I used mostly steel wool to clean and polish the chrome and aluminium parts of the engine. Steel wool is really great and better than sandpaper because it will not scratch the parts like sandpaper does, and it also make them shine :)

And I also changed many parts like handlebars, grips, levers, etc. to match the rest of the bike and changed about every nut and bolt with new stainless steel ones.

But one thing I like a lot on this bike is my custom hand made seat that I built entirely myself!

Now it is time to enjoy that salvaged bike and make it ride again on the street it probably rode on about 40 years ago!

I always find it satisfying and impressive to think that a vehicle that is almost twice your age can still run after a restoration.

I think we probably all have already seen or knew someone who had a junk motorcycle sitting and rotting in their backyards for decades, now you know that it can always be restored and you know what are the main steps you need to go through to make a bike run again!

But remember to always ride safe!! before the first ride (and also every other ride), make sure all the bolts are secure, brakes are working, tire pressure is good, etc.! Always do a checklist in your head to see if your bike is really ready to ride or if you still have to go through some steps!

And ride it slowly first to see how it behaves ;)

As for my little Honda 350 Four, is it super fun to ride, the low seat and center of gravity on those old Honda's CB make them super easy to ride, like a bicycle!

This salvaged CB 350 Four will now be exposed at the Cafe Racer Festival on June 23 in France in the Shed build contest :)