Squirrel Power: Making a Minibear Part 1
by David Zipf
It’s been a while since we talked about our little Suzuki FA50 runabout. You’d be forgiven for thinking it had been abandoned or sold. But fear not! Neither is true. In fact, this thing has been the perfect little around town commuter, running beautifully for the last year and a half. Aside from a minor oil pump problem, we’ve had almost no trouble with our little Suzuki. Unfortunately, it is still as slow as ever and we really need to fix that. And fix that we shall!
Our engine rebuild is going to take place over a few stages. The first step is relatively straightforward: a larger carburetor to allow more air and fuel into the engine. It’s going to be a bit oversized for our current application, but will be necessary to support our engine mods down the road.
The carburetor we went with is a Mikuni VM18. It’s an incredibly versatile carb and is the choice for a huge range of bikes. It is a slide carb with a manual choke lever, using a clamp style intake mount seen here. This carb can be used for two or four stroke engines. Best of all, Mikuni offers a huge range of jets, everywhere from 50 to a 720, so there are lots of fueling options for this carb. We’ll be sticking with the smaller end of the scale with our 50cc motor.
This carb is more or less bolt in for our engine. Suzuki originally equipped the FA50 with a VM15 carb, which is a bit smaller and also uses a bolt on mount. The VM15 uses a cable operated choke, which can be operated from the handlebars.
To adapt the VM18 to our FA50’s engine, we need a new intake. Motion Left Mopeds (or MLM) offers this intake specifically for mounting VM18s to the FA50’s engine. Not only does it convert the clamp on mount to a bolt in type, but it also acts as the elbow to clear the fender. The VM15 carb is nestled on top of the engine between the frame and the rear fender and the larger VM18 simply doesn’t fit in this space. Finally, the MLM intake adds an extra vacuum port for the fuel petcock, allowing the VM18 to be a perfect bolt-on replacement for the VM15. Both the carb and intake came from our favorite moped store, Treatland.
On the VM15 carb, we attached a K&N breather filter to our original intake elbow. To make it cinch on that elbow, we needed a filter with a 1 ¾” opening. The VM18’s position allows us to clamp the filter directly onto the carb and the intake portion of the carb requires a 32mm filter. A 1 ¼” filter is 31.75mm and allows us to stick with the K&N family. Once again, we went with a filter that would normally be found on the breather of a big ol’ drag racing engine.
Any updates on this lil fella? I just picked one up for free.
It’s still in my garage, waiting on me to get around to do this engine rebuild. Right now it’s just way too cold to do a lot of garage work, but I do plan on rebuilding the motor sometime this year. Too many projects on the plate, but this one WILL get pushed back to the front!
I have the same bike almost to a T and was hoping you might be able to give me some tuning advice.