I’ve been working on a project, modifying my 1980 Honda Nifty Fifty 50cc scoot to a high performance beast. I’ve made this thread to help anyone who might try to do the same type of project.
This is what a standard Honda Nifty Fifty looks like (in Japan they are called Honda Eve, and in Europe/America there is a similar bike that's called a Honda Spree)
Metal sleeve to mount shock on
This is the original Honda Nifty Fifty engine mount bracket
Since it will take a bit of time to get the frame back from the powder coating, in the mean time I decided to bead blast the variator/transmission cover. I’ll probably also polish the covers when I get time, but for now I think the finish is quite nice.
Rear variator cover before bead blasting
Some of the panels will need to be cut/modified to fit over the new components like motor, front forks etc. My plan is to try to fit them once the motor and suspension is all taken care of… then when I know what needs to be modified I will cut the panels and prepare them for a paint job.
Dio SR front forks in Nifty front guard, as you can see they dont fit... yet
Now that the motor and shock were attached I could see there wasn’t enough clearance between the back of the frame and the top of my rear tire. The new shock is actually shorter and stiffer than the standard Honda shock. I will need to return it to the store and get the next length up (8cm longer), which should be the perfect length.
Clearance between rear tyre and Nifty frame is tight
Shrink wrapped handle bars
The stem on the Dio forks will also need to be shortened as it's a fair bit longer than the standard Nifty fork stem. I'll probably do this by cutting a segment out of the middle of the stem...
Dio SR front forks and shocks
Attaching a new motor also meant the shock mounting point needed to be moved further back, because the new motor is longer. To do this I needed to make up a metal sleeve and drill a hole in the frame to mount it in.
This is the shock in place, the bolt to the far left of the picture is the previous mounting bolt… you can see much further back it has become
My initial plan was to replace the standard AF05E motor with Honda’s more powerful AF18E motor (both are 50cc). I was told the AF18E would bolt right up, but I soon found out that’s not the case. This is because the new motor was from a 1990 Honda Dio SR, which has an entirely different frame to the Nifty.
So I needed to modify the engine mount bracket on the Nifty Fifty’s frame.
It took a few attempts to get the bracket design to a point I was happy with, but the bracket is now complete and welded onto the Nifty’s frame.This is an early engine mount bracket prototype design, it turned out to be quite close to the design I would end up using.
While the frame is getting painted I decided to check how well a Honda Dio front wheel and tire would fit in the Nifty Fifty forks. It turned out that it couldn’t at all.
This means I could either continue using the skinnier Nifty Fifty front wheel and forks/shocks, or I would have to replace the entire front end assembly with another scooter… I chose to change the front end to a Honda Dio SR front end. The 1990 Honda Dio SR came with front disc brakes, so I will have to attach these as well.
This means my Nifty Fifty will now have a Dio SR motor, Dio SR rear brakes, Dio SR front disc brakes, Dio SR forks.
Unfortunately the Dio SR forks are rusty and leaking oil, so I will need to remove them from the forks and replace them with new shocks. The new shocks are already being shipped to me.
Dio SR front hydrolic brake booster
Front and rear variator covers after bead blasting
Once the shock was mounted I could see how the bike looks with the new motor in place.
Picture of motor attached to the frame for the first time.
The frame modifications are now complete, so it’s time to prepare the frame to be painted. To do this I bead blasted all the paint and rust off the frame and handle bars. Then I took them in to get powder coated… I can’t wait to see what it looks like when the powder coating is done.
Shrink wrapped frame
This is the original Honda Dio SR engine mount bracket
This is a comparison between the stock Nifty Fifty bracket, and the new custom one
