The Long Haul Part 6: Putting the final touches on our 1974 Honda CB450

The Long Haul Part 6: Finishing Up our Honda CB450

The Long Haul Part 6: The Finishing Touches

Texas to Ohio to Minnesota and Back Again on a 1974 Honda CB450

We've arrived towards the end of our Long Haul project: call it a build, refurbishment, tune-up, whatever. The bike is to a point where the parts that make it run good have either been replaced, cleaned, or rebuilt. The most appropriate term is probably mechanical restoration.

Most of us here at Common Motor are in the camp that these bikes should be actively maintained and ridden - a lot; not meticulously polished for Instagram or the showroom floor. You've probably noticed that aesthetically I go for simplicity and functionality over flash or perfection. Just how anal & obsessive or fast & loose you choose to be with your bike is ultimately up to you and your priorities as a vintage motorcycle owner.

The last few parts we're about to talk about include plenty of personal taste, and are the parts that many folks start with when doing a "custom build" due to their ability to substantially alter the look of the bike. You'll notice that we saved them for the end - where they should be after all of the severely important stuff.

Intake and Exhaust Geometry

Since the air filters had to come off to rebuild the carbs, and the exhaust headers had to come off to replace the gaskets and get into the engine side-cover, both need to re re-installed.

Pod filters are very popular for their looks, simplicity, and weight. I decided to run factory-style air filters for a number of different reasons. Not only are our factory-style CB450 air filters a new product that needs thorough testing, the larger filter surface area and their location behind the side-covers make them more resistant to dust, grime, and rain. We've also found that, without the support of the factory filter, the carbs' weight puts an undue stress on the rubber intake manifolds, which can crack where the mounting sleeve meets the flange. Pods are fine, but it is recommended to support the carbs some other way; with a short cable up over the frame perhaps. That, or just be prepared to change out your intake manifolds every-so-often.

Mufflers are another very common aftermarket "upgrade" made to these bikes, partially because the original mufflers tend to be rusted through or missing altogether. Fortunately there is no shortage of slip-on mufflers on the market. As we go about testing various models to add to our product catalog I decided to try out some basic, baseball-bat-looking mufflers with a reasonable amount of packing and restriction. While shopping for mufflers can often be governed by their looks, the inside geometry is more important. The less packing and restriction, the louder they will be and the static pressure the engine sees when when the exhaust valve opens will be relatively low - not necessarily good for performance and fuel economy. The mufflers we currently carry on our site, and any we may add in the future, are as closely matched to the style and geometry of the factory mufflers as possible.

Tank & Seat

Since we have a small collection of CB450s in various states of disrepair, there were a few parts I had some unique options on. The tank and side covers that originally came on the bike had been repainted maroon, and while they had been sprayed fairly well they definitely had a more modern, generic, and subdued look to them. I decided to go with a bright red/gold tank and a set of matching red side covers instead. The important part was that the tank was clean on the inside and none of the parts were damaged so much as to affect their mounting geometry or functionality. The original emblems were definitely a bonus.

I installed a new petcock and plumbed up the tank with some clear polyurethane tubing. The fit between the tubing and the fittings is tight enough I haven't had to use any hose clamps, but i'll certainly bring along a handful of squeeze clamps and small zip ties should that change.

The seat that came on the bike is original and still in great shape so I plan to run it as-is. I may bring a small pillow or something to sit on, since even the most comfortable seat starts to feel like concrete after a few thousand miles. One of the mounting brackets needed to be welded back to the seat pan, but that wasn't a problem.

Road Trip Mods

Speaking of welding, I needed some way of fixing my luggage to the bike. There are countless ways of going about this, but i've found the most important thing to consider is the weight distribution between the front and rear of the bike. Just like loading a trailer, if too much weight is at the front or the back your stability at high speeds can be severely affected potentially causing a wobble that can turn catastrophic.

Trial-and-error has taught me that keeping some weight up front on these little bikes, either with a fork bag or tank bag, can make all the difference. I'm planning on using both in addition to gear towards the back. The tank bag should be fairly self sufficient, as it clips around the bottom of the gas tank. There are a lot of universal tank bags on the market. Make sure whichever one you go for has mounting hardware that will work well with your specific bike and gas tank. A cargo net stretched around it will also help keep things in place.

For the fork bag mount/headlight bracket and rear luggage rack I've rescued a sissy bar and passenger handle off a parts bike. These were of questionable quality as aftermarket parts back in the day, but with some cutting, welding, and grinding they should be more than sufficient for our purposes. The handle and an old highway bar became a funky headlight bracket and mount for a barrel-shaped tool bag under the headlight. The sissy bar just needed a few repairs and will be perfect for strapping down my main bags, tent, and sleeping bag.

Long Haul CB450 loaded up with fork bag, tank bag, dry bag, tent, sleeping bag, & backpack

Shakedown Run and Final Adjustments

To flush out any last gremlins I decided to take our Long Haul bike from Houston out west past San Antonio. It didn't hurt that some friends had rented a cabin that weekend to float the river. After that 500 mile round trip in the Texas Heat a few things became apparent.

The 5-speed transmission on the 450 struggled to keep up at highway speeds for a prolonged period of time. Just like on a bicycle, a larger front gear (and/or smaller rear gear) allows for greater speed at the expense of torque and vice versa. I opted to install a larger front sprocket and smaller rear sprocket. Not only did this change the gear ratio to favor top-end speed over low-end torque, but it allowed me to keep the same length chain that I had installed initially.

Swapping out sprockets
Changing Sprockets

A few smaller details needed attention like a shakey tachometer, blown instrument bulbs, minor exhaust leaks, etc. which didn't take long to rectify.

With the bike mechanically sound the last step is getting any and all tools, replacement parts, personal bags, and camping gear organized and fitted to the bike. The video above shows all the tools an extra parts that we could think to bring, but in short our tool kit included the following:

Original Honda Toolkit (wrenches, screwdriver, pliers, shock preload wrench)
Adjustable Wrench
Set of Metric Allen keys
Rubber gloves
Fuel line, clamps, and zip ties
Replacement brake & clutch levers
Small assortment of different sized main jets
Test-light and small multimeter
Spare bulbs & fuses
Chain lube
Spare tubes, tire levers, CO2 cartridges, & air pressure gauge
2L fuel can
Spare Qt of motor oil

When mounting your gear make sure to connect straps and cords to secure locations on the frame or other solid mounting points. Redundancy is key in the event that a bungee cord or cargo net snaps or comes loose. I say this from experience: don't take this step lightly as the way you mount your gear could be the different between a smooth, easy ride, or half your stuff scattered across the road because you didn't secure it adequately. It also tends to be an iterative process that gets tweaked along the way. So, stay tuned for the next exciting installment of our Long Haul CB450 Project: The Road to Mid-Ohio!

Ready to Roll out - Ella says goodbye
Ready 2 Roll