How to build a custom Postie bike

How to build a custom postie bike

From sourcing a donor bike to the tools you’ll need, a bike builder reveals the tips and tricks that will transform your Postie bike from boring to jaw-dropping.

Once upon a time in the suburbs before email / insta-snap-tok-face messaging became the norm, the only way you could slide into someone’s DMs was through a handwritten letter. There wasn’t a sound more joyous than that of the postie’s single cylinder tearing up the footpath on the way to deliver your bae’s letter, only to find out it was a reminder for your overdue library book.

As it turned out the humble Honda CT110 Postie became quite the Australian icon years after it was introduced by Australia Post in 1980. Its appeal stretched across a wide audience, and rightly so. The single-cylinder 110cc engine was renowned as being bulletproof with a number of events and charities using posties to ride ridiculous distances that would put a modern day tourer to shame.

Up until 2013 Australia Post put it’s faith in the trusty CT110 to deliver mail to thousands of Australians, as it was not only reliable but provided good bang for buck. Something that couldn’t be said for other bike manufacturers with names rhyming with Hardley Jamison.

How to build a custom postie bike

In 2013 it was decided Australia Post would retire the red rocket and make way for the more fuel efficient but less stylish NBC110 Super Cub.

In the coming weeks and months, we’ll be exploring all the different types of custom motorcycle, but for the novice bike wrencher and expert alike, customising a Postie can be a lot of fun. The Postie makes a great first custom build because of its simple and manageable design, easy-to-maintain motor, lower ride height, lack of full manual transmission as well as being learner approved.  

Whether you decide to customise it yourself or get a workshop to do the build for you is a personal one. There are a couple of deciding factors for both, most notably budget and time; if you’re somewhat mechanically-minded and willing to get your hands dirty spending a healthy number of hours working in the shed then there’s no better way to learn a few new skills and get the satisfaction of something you’ve built with your own hands..

But like a famous internet meme once said: “There’s only one thing more important than time and that’s what you spend it on”.

So if spending hours and hours covered in oil and grease isn’t your thing, then maybe getting a commission build is the better option. Not only can you spend your time focussed on other life skills, more often than not you’ll be able to ride it away into the sunset without having to spend money on tools you may or may not need in the future.

How to build a custom postie bike

Space is another key deciding factor, even though I’ve seen bikes built in hallways and bedrooms before; sorry Mum. Having a little extra room to move makes a big difference, especially when it comes time to paint, clean or have your friends over for a beer to admire your handiwork or express concern over your 7.5HP midlife crisis.

If you do decide to have a go yourself, then great, it’s time to find a donor.

How to source a Postie bike for your build

When looking for a donor Postie, most of them these days will have done more than 25,000km, however you may get lucky and find one with lower kays. As they’re no longer used by Australia Post prices have increased and days of finding a reasonably priced Postie in excellent condition are almost a distant memory. Expect to pay anywhere from a few hundred bucks to several thousand dollars.

How to build a custom postie bike

You normally want to find one in overall good condition as it’ll save you time with any bodywork and replacement parts that you’ll need to look at down the track. Make sure the rims are straight and aren’t pitted from rust. Check the bike starts and there’s no weird knocking sounds coming from the engine, make sure there are no large clouds of smoke coming from the exhaust, too.

How to build a custom postie bike

Take it for a spin and check that you can shift through all the gears. You can also pop it onto the centre stand so the front wheel is lifted and move the handlebars side to side to make sure the head bearings are ok – though it’s not a big deal to replace these after teardown. Lift up the seat and have a look in the fuel tank to make sure it’s not rusted out. Last but not least make sure the frame has a compliance plate otherwise you won’t be able to register it for the road.

How to build a custom postie bike

If you find one that is pre-93 it’s more likely to be 6V so you’ll need to make sure any aftermarket electrical parts that you buy will be suitable.

If you’re replacing most of the stock parts with aftermarket then everything else is a bonus. 

What tools will I need

Most of the work can be done with some simple hand tools. Sure you can spend money on specialty ones but with a little patience you can achieve similar results.  If you don’t have that kind of patience either pick up some of these tools or see points about getting a custom shop to do the work for you.

First you want to get yourself a service manual. It has everything you need to work on the bike, from correct torque settings to wiring diagrams, and just like any Beach Boys album it’ll get you through the tough times. I’d recommend picking up a good set of metric sockets, spanners, and allen keys. This will take care of most of your tear down and assembly.

How to build a custom postie bike

For fabrication you might need an angle grinder to remove any unwanted frame tabs or to shorten the fenders, again you’ll need to check with your current legislation to see how much you can remove.

Depending on your build you may also need access to a welder, a Mig welder I find is quite versatile with the type of work I do it’s handy for making brackets and attaching mounting points to your frame. But if you need any detailed work I’d probably suggest a Tig. We’ll explain how to use Mig and Tig welders in another article.

A drill will also be handy with some stainless steel bits to help with making brackets or attaching any aftermarket parts to the frame.

If you’re changing the fork seals you might also want to invest in a fork seal driver and fork seal remover. These can save a bunch of time and prevent you from gouging out your forks. If you need to replace the chain a chain breaker will also need to be on the shopping list.

Electrics When dealing with the electrics you’ll want to pick up a stripper, a wire one that is, you filthy animals. You’ll also need a soldering iron to help extend any wiring and join any connections. A multimeter also comes in handy if you need to troubleshoot any electrical issues.

What skills will I need?

You’ll need some basic mechanical knowledge, but if you decide to rebuild the engine and hone the cylinder then it’s probably something that needs to be covered as part of a more advanced article. You’ll also want some basic electrical knowledge, if you did physics at school then that’s probably sufficient, if not then it’s not a big deal, you may not need any fancy equations if you’re just adding a new pair of indicators or taillight. Having a little knowledge will also help with any of the more complex wiring situations along with reading the diagrams.

If you want to paint the bike yourself, having previous spray painting experience either with spray cans (tagging doesn’t count) or a spray gun will always help getting a clean finish. It could save you hours of sanding back and redoing everything again.

What parts should I budget for?

If you’re looking at replacing most of the stock parts you can really go to town with aftermarket parts. Unless the donor had new tyres then a fresh set of rubber is always a good start. I think the best return on investment parts in no particular order would be the seat, headlight, handlebars, taillight, indicators, speedo, exhaust, and grips. You’ll also need to take into account the perishables, costs of stripping the paint, cleaning, and painting the frame and any parts.

I like to keep track of all my expenses and what needs to be done via Buildboard which is an online project budget tracking tool that we wrote to keep track of our own builds. Alternatively you can use a notepad or an excel spreadsheet.

The build itself

For most builds I normally like to start off with some kind of sketch / concept. I know some builders don’t work from any kind of concept and they let the process dictate how the build pans out. However for me I find it lets me mentally map out what needs to be done, and it’s always a good reference point to make sure you’re heading in the right direction.

Once you’ve got a rough idea in your head and an idea of what parts you need, you’re ready to start removing the parts that you won’t need for a mockup. That way when your parts arrive you still have a shell to check for fitment and clearance.

How to build a custom postie bike

When removing parts from your bike make sure you have some kind of parts cataloging system. This can be something as simple as writing the part name on a bit of masking tape and taping it to the part. For smaller items such as mounting bolts it’s nice to have them boxed up together with a label on each, e.g. ‘left engine mounting bolt’.  It’s also handy to take photos along each step of the process so you can refer to them later on down the track – you can never take too many photos.

If you need to make any changes to your bodywork or add new mounting points or brackets now is the time.  Here you can mockup exactly how your parts will fit without worrying about damaging the finish.

Once you’re happy with how everything sits together you can remove the remaining parts and start cleaning and prepping your parts for paint.

You’ve got a couple of options with cleaning your parts, if you decide to do it yourself you can use a wire brush in your drill to clean most steel surfaces. Otherwise if you can afford it you can send your parts off to get sandblasted and powder coated / painted.

While you’re literally waiting for the paint to dry now is a good time to clean up the engine and flush out the carb. Depending on the condition of the carb gaskets, getting a carb rebuild might be worthwhile.  

What shouldn’t I try and do myself?

Unless you’re an engineer, know of someone who is, and have access to getting your modifications certified, you want to try and avoid any structural changes to your frame. It can be costly for both certifications as well as your general safety. The last thing you want is for your frame to snap mid mono while trying to impress the lunch lady down the road.

Every other modification you just need to make sure you adhere to your local state laws and design regulations. Most of the information can be found online and makes for some excellent bedtime reading.

What do I need to know about painting my bike

If you’ve got some spare budget I’d really suggest sending your parts off at least for sandblasting. Paint stripper is toxic and so is the dust that comes off when you remove paint with a wire brush.  It’ll save you plenty of time and you’ll get a really clean result to work from, as they say with painting preparation is key. 

In terms of finish you’ve got the option to either spray it yourself, get it professionally sprayed or get it powder coated.

Again it’s one of those things if you’re wanting to learn how to spray your bike you can pick yourself up a spray gun and a compressor and try it out. You will still want a clear coat and if you want a lasting finish you’ll get it professionally cleared with a 2-Pac clear as spraying this is not allowed without the proper equipment.

Another option is to use some Epoxy enamel spray cans to spray your bike, not all brands are created equal so you’ll want to try it out on some test pieces first.

Alternative you can get your parts powder coated or professionally sprayed. Much like oils there’s been debates about which finish is better. Really it’s a personal preference, but generally I like to get rims and brackets powder coated as I know that I won’t need to make any further modifications to these.

Again professional painting is an art in itself so just be aware that you’ll never get the same result as getting a professional to do it.

Basic tweaks to make your postie bike stand out

Normally when customising a bike the two key elements are the tank and the seat. The way they flow together really makes up the overall aesthetic. The Postie’s tank however is under the seat so making it stand out from other posties is a little trickier. One thing that can make a big difference is the seat, and by changing this you get a chance to play with the lines and theme of the bike. Other items can be the handlebars as the original postie bars are quite high so switching them out to something lower or wider can make a big difference, there are a multitude of options available when choosing bars, again it really depends on your design direction.

How to build a custom postie bike

Another key factor is the paint scheme, picking any color other than the Honda Red will automatically make your custom Postie stand out.

In terms of performance a common modification is to remove the old air box and add a pod filter.  This will mean you’ll also need to rejet the carb to allow for the extra air.  So while your carb is off for a clean it could be a perfect time to swap in a new jet.

So you wanna turn your Postie into a cafe racer

There are quite a few different categories custom bikes generally fall into, and the frame and stance of the postie lends itself better to some than others.  The following is just a general guide and by no means a set of rules to adhere too.  As with any creative project rules can be broken as long as they’re not road variety.

The history of the cafe racer can be traced back to London in the 1960s where all unnecessary items would be removed from the bike to make them as light as possible, it was motorcycle minimalism and was the cheapest and easiest way to improve your bike’s performance without aftermarket accessories or tuning. These days a bike is classified as a Cafe Racer when they are seen with clip-on bars and a single seat with a rear cowl. Having the clip-on bars and cowl lets the rider tuck into a more streamlined position to improve the aerodynamics by increasing air flow over the rider and the bike.

To achieve a similar look with your Postie you’ll want to start removing some weight, overall the Postie is quite minimal already but there are a few that could shed a few pounds. Removal of the luggage rack is a good place to start, following that the OEM tail light assembly. The Postie also comes with both a side stand and a center stand so deciding on one or the other will also help. The mirrors and indicators can also be replaced with smaller more lightweight alternatives.

To get that racer position you’ll also want to find yourself a set of clip-on bars that will fit the Postie forks. Alternatively a set of clubmans might be what you’re after.

So you wanna turn your Postie into a Scrambler / Tracker

In a similar vein to the Cafe Racer the scrambler too was born from necessity. But this time it wasn’t the cobbled streets of London but rather off-road courses where terrain was unpredictable. Bikes were stripped back to the bare essentials, with the key focus on having good ground clearance and a more comfortable riding position for the uneven terrain.

The exhausts were also raised higher than normal to clear any water hazards along the way, along with a set of knobby tyres to keep the bike upright.  The modern scrambler shares many of these traditions however a large majority of them won’t see the type of conditions their predecessors saw.  Along with the aforementioned features, add in a longer flatter seat and you’ve got yourself a bike to take on any urban environment, with the occasional dirt track thrown in.

To turn your Postie into a Tracker you’ll want to look at getting yourself a set of wider tracker style bars. Similar to the Cafe Racer you can also remove and replace unnecessary OEM stock parts.  

As for the seat you’ll want something a little longer than the stock, you’ll also need to take into consideration the mounting as you’ll still need access to the fuel tank.

If you plan on taking it for a blat off-road or just prefer the look, a set of knobby tyres can be what you’re after.

The current postie exhaust already fits into the scrambler vibe so a fresh coat of exhaust paint might give you a nice point of difference.

There are a multitude of approaches one can take in customising a Postie, this is just a brief overview as each section could have it’s very own article.  Whether you’re doing it solo, with a buddy, or family crew, it’s something that should be fun and give you some new skills along the way.  As long as you have a general direction and some patience then there’s no reason why you can’t deliver your own custom postie.  And as my riding instructor once told me, you lower the CC you increase the fun.

*disclaimer: Do not take this advice as gospel, modify your motorcycle at your own risk, one should perform due diligence before undertaking such modifications. Please make sure you adhere to all road rules for your designated state or territory.