The Fastest Postie Bike

The Story

 

Started in 2022, the second build in the Crane-o garage. A build that I was looking forward too starting for a long time. I'm a postie myself and one day I was looking at the bike thinking you could probably fit a 1000cc engine in there, so it got me thinking. The CT110 is such an iconic bike especially here in Australia, and they have heaps more room for activities. 

 

One morning I saw an old CT110 up for sale for $200. Wasn't really looking for one at that time, nor did I have any cash spare, so I let it go. That afternoon it was still for sale but for $100. Now that was a deal I could not pass up. Picked it up 30 minutes later. The bike wasn't running at the time. But after cleaning up the carb, I was riding it around the backyard. 

 

It took a while before I was ready to start the project, but I knew I wanted a modern 1000cc. Wanted something with at least traction control as it is gonna be pretty rowdy. It also had to be a Honda engine. I ended up with a wrecked Honda VFR1200, (it was a good deal). Not exactly what I was after, but it was a deal, and V4's are amazing. Honda claims they have 170hp at the crank, so the engine has potential. By the way, that's over 20 times more powerful than stock. 

 

The VFR engine is shaft drive which makes this build a bit tricky. But I have plans to convert it to chain drive, machine a new side case and output shaft. Should pick up a bit of power, as the stock driveshaft assembly weighed almost 20kg. My original design was to take the transmission output shaft and esstialliatly remove the bevel gear that turned the drivesahft and put a sproket on than instead. This would mean i would only need to make a new part of the engine case. this however, would not be the case. I had completly designed this new case and had it 3D printed in aluminium (not cheap, but had oil passages the needs to use from the stock cast peice). This was going great. i was a bit limied on frnt sproket choice as the clutch slave cylinder was close by but it was an easy solution, it didn't it have to be very accurate either as the bearings for the output shaft were located in th engine block.

At some point i started think about gearing ratios and working out what i need to go really fast, as i started thinking about the VFR1200 shaft drive and the gears i had removed, i realised that the VFR1200 has 4 gears that i removed that formed part of the shaft drive. And it hit me, i started doing a bunch of visualtions in my head. I went out to the garage turned the entgine over and realised that the output shaft turns in reverse compared to the rear wheel. still working out how to fix this but it will envolve a small gear box mou8nted to the output shaft to get it to turn the correct way. But its not all bad. the sproket will be higher, which will allow for better geometrey and also allow me to run much bigger front sprokets. However it is about 8cm further out than my original plan. which will mean more modifications to the rear wheel

 

Now that I have a bike and an engine. Time to get started. The 1200 is quite a bit bigger so I had to cut a bit of the CT frame to make the engine fit. After building the new engine mounts and getting the engine in, the wheelbase was only extended 5cm compared to the stock CT. Added a bit more rake to help with stability at high speed. 

 

Unfortunately the VFR did not come with a key. Australian bikes have an immobiliser, and Honda do not make it easy to get around them. So I decided it would be easier to get a new ECU. So I got my hands on a Haltech Elite 1500, a very very nice bit of kit, and will let me run a lot more stuff than the stock ECU could. Such as traction control, auto blipper(clutchless full throttle up and down shifts), launch control. 

 

There is no official Guinness World Record so it is hard to verify who actually holds the current record but I believe it is 206 km/h which the CT1200 will do on the back wheel. The CT1200 is far front stock but neither is the current record holder, they all have some sort of modified frame. I will try my best to keep it looking as stock as possible. Unfortunately I'll have to switch out some suspension and brake components for safety.

 

The biggest challenge so far in this build is fitting everything on the bike. Not only do I have to fit an engine that's over 10 times that original displacement, it needs an ECU, Battery, fuse box, ignitor module, rectifier, fuel pump, fuel regulator, wideband controller, dash. I’ve managed to keep the stock battery box as is to house the lithium battery and ignitor module. The air box has been slightly modified, as it is more of a cover now for the ECU. And I've made a hollowed out seat with carbon fibre to house the fuse box, rectifier and wide band controller.

 

I have big plans for this build, and its just beginning so stay tuned!