How to Strap a Leaf Blower Engine to a Bike and Go Fast

Step 7 Results + Video

This video was taken on an improvised oval track. I was holding about 20 mph throughout the run.

Here's a video of a "high-speed" run (about 25 mph) down my street. I hadn't added the hand throttle yet so I had to pull the engine's original throttle cable to accelerate, which is why I'm awkwardly leaning over the front of the bike.

Starting Procedure
To start the bike, I use the standard priming and choking procedure. This usual includes a priming until the bulb fills with fuel followed by a quick pedal start with the engine fully choked until it kicks over. Once their is fuel in the lines, I open up the choke to the middle setting. The motor starts when the bike is pedaled to around 8 mph, which can take some furious pedaling, but isn't too bad. The bike is even easier to start when it's hot. At about 12 mph the bike has enough power to start accelerating up to speed.

Performance
Acceleration is very sluggish at low speeds, but over 15 mph the bike zooms along with adequate acceleration. According to the bike odometer I have attached, it has hit about 29 mph on a slight down hill. It can go up significant hills and still hold 15 mph. Average speed riding around the neighborhood is about 18 mph. If you think of the machine as a bike with a power-assist rather than a mini-bike, it is very reasonable. With a little gas it is effortless to cruise at 20 mph, a speed barely attainable on a downhill when pedaling this bike. Since your rear is near the ground, it feels even faster than it is.

Is it worth it?
For all of the frustration that comes with keeping the machine running, the question you have to ask yourself is: Is it worth it? Well, as long as you enjoy hot exhaust blowing on leg and the wind in your hair while flying down the road at obscene speeds with a small two-stroke between your legs screaming at 7000 rpm, it is definitely worth it.

Comments

[norrisj]

Could you put this motor on the back of a mountain bike?

[Jnkyrdguy]

As long as there's something to mount it to back there, you definitely could!

[norrisj]

sweet thanks man ill try it this summer

[Mavamaarten]

Can I have your babies pls ?

[JCoffey]

That is Great! Sears used to sell something just like this years ago and I always wanted one. Harbor Freight sometimes sells remanufactured 25cc Weedeaters, and they have a clutch, so I bet you could use one of those and mount it to the rear tire for better weight balance!

[Jnkyrdguy]

Having the engine hang off the front isn't too bad for balance. Compared to my weight, the engine is small enough you can still easily control the bike. You do have to keep at least one hand on the handlebars at all times though, but that's probably a good idea anyway ;)

[thinkdunson]

i can't imagine ever mounting anything to the forks. i know you say that you can still "easily control the bike", but that would just totally screw up the steering. i've always wanted to mount an engine with a chain connecting it to the large sprocket on the front crank. then you'd be able to shift gears with the rear derailleur!!!

[LetsExplodeSomething]

yes then you could maximize speed acceleration and fuel consumption

[faranume]

ammmm hey. I was wondering about the weight of the bike and the engine , if you could tell me, that'll be great Thanks, nice Instructable

[Prometheus]

That bike would weigh about 25 lbs (no "BMX" bike weighs less than 20 lbs that is not carbon-fiber) and the engine and kit could be estimated at about another 10 lbs....Still a significant power-to-weight ratio overall. Maybe 40 lbs as a maximum....Try your bathroom scale for an estimate, I do it all the time.

[Jnkyrdguy]

I don't know the exact weights, but I would guess about 15 lbs for the bike and about 5 lbs for the engine.