Build a simple frame, mount a chainsaw engine, add clutch, chain, and brakes.
If you’ve ever wondered how to make a chainsaw mini bike, you’re in the right place. I’ve built and tuned these little rockets in a home garage, and I’ll walk you through the entire process. Expect clear steps, smart parts choices, gearing math, and safety tips that actually matter. Read on to learn how to make a chainsaw mini bike that starts easy, rides smooth, and doesn’t shake itself apart.
Before You Start: Safety, Scope, and What You’ll Build
You can build a fun, off-road mini bike with a 35–62 cc two-stroke chainsaw engine. It needs a strong frame, a reliable brake, and a well-aligned chain drive. This guide covers safe setup, proven gearing, and beginner-friendly steps for how to make a chainsaw mini bike.
Safety is not optional. Wear a DOT-approved helmet, eye protection, gloves, long sleeves, and boots. Work in a well-ventilated space. Two-strokes make fumes and noise. Check local laws. Most builds are for private property or off-road use only.
Tools and Parts You’ll Need
The right kit makes or breaks the build. Here’s what I use when showing friends how to make a chainsaw mini bike.
Parts
- Chainsaw engine in good shape, 35–62 cc two-stroke
- Centrifugal clutch matched to your crankshaft diameter and rpm
- Sprockets for clutch and rear wheel, plus chain (e.g., #35 or #41)
- Jackshaft kit if you need extra gear reduction
- Frame material, like 1-inch steel tubing or a donor mini bike frame
- Wheels and tires, 10–12 inch diameter
- Rear brake, mechanical disc or band brake, with lever and cable
- Throttle assembly and cable compatible with your carb
- Kill switch mounted on the handlebar
- Fuel tank, fuel line rated for gasoline, filter, and shutoff valve
- Chain tensioner and chain guard
- Engine mount plate, steel hardware, washers, locknuts
- Spacers, bearings, and pillow blocks if using a jackshaft
Tools
- Angle grinder, MIG welder, drill and bits, files
- Wrenches, sockets, torque wrench, screwdrivers
- Measuring tape, calipers, straightedge, marker
- Chain breaker and master links
- Safety gear: eye and ear protection, gloves
I keep spare spark plugs, premix oil, Loctite, and anti-seize on hand.
How the Drivetrain Works (And Why Chainsaw Engines Are Different)
Chainsaw engines make power at high rpm but low torque. A centrifugal clutch grabs at a set rpm, then drives a small sprocket. That turns a chain to the rear wheel sprocket. To ride well, you need reduction. That means a small front sprocket and a big rear sprocket, or a jackshaft that adds another step of reduction.
For how to make a chainsaw mini bike that pulls from a stop, aim for 10:1 to 13:1 total ratio. That helps the engine stay in its powerband and saves the clutch from burning up.
Step-by-Step: How to Build the Bike
This is the clean, repeatable path I use when teaching friends how to make a chainsaw mini bike.
- Plan the layout
- Place wheels, seat, and bars for a natural ride stance.
- Mock up the engine location with wood blocks.
- Keep the chain line straight and the weight centered.
- Build or prep the frame
- If you weld, bend and weld 1-inch tubing into a simple rectangle with a head tube.
- If not, use a donor mini bike frame and adapt mounts.
- Add gussets at stress points.
- Mount the engine
- Use a flat steel plate with slotted holes for chain tension.
- Add rubber isolators if the vibration is harsh.
- Align the clutch sprocket with the driven sprocket.
- Install the drivetrain
- Pick a clutch sprocket (often 10–12T).
- Pick a large rear sprocket (54–80T) or add a jackshaft.
- Set chain tension with 1/2 inch of slack at the tight spot.
- Add brakes and controls
- Mount a rear disc or band brake. Test lever feel.
- Install throttle and a positive kill switch on the bar.
- Route cables with smooth bends and secure them with clips.
- Fuel and exhaust
- Mount a small tank away from heat.
- Use fresh fuel line, a filter, and a shutoff valve.
- Point the exhaust away from legs and plastics.
- Final checks
- Every bolt gets threadlocker or locknuts.
- Spin the wheel and check for chain wander.
- Squeeze the brake. It should lock the wheel on a stand.
A note from experience: my first build ate a clutch because I used 6:1 gearing. I swapped to 12:1 with a jackshaft. The clutch ran cooler, and the bike finally pulled hills.
Gearing Math Made Simple
Here’s an easy way to plan gearing when figuring out how to make a chainsaw mini bike.
- Find your engine’s happy rpm. Many chainsaws like 6,000–9,000 rpm under load.
- Pick a target top speed. For a small yard bike, 18–22 mph is plenty.
- Wheel rpm at 20 mph with a 10-inch tire is roughly 530 rpm.
- Total ratio = engine rpm divided by wheel rpm.
Example
- 7,000 rpm engine / 530 rpm wheel ≈ 13:1 total ratio
- You can get 13:1 with a 10T clutch and 65T rear sprocket (6.5:1) plus a 2:1 jackshaft stage.
Tip: start high on reduction. You can gear taller later if it feels too slow.
Wiring, Fuel, and Controls
Clean wiring and fuel lines keep you safe while learning how to make a chainsaw mini bike.
Wiring
- Wire the kill switch to ground the ignition when pressed.
- Keep wires away from the chain and exhaust.
- Use heat shrink for strain relief.
Fuel
- Use a fresh fuel line rated for gasoline and ethanol.
- Two-stroke mix is often 40:1 or 50:1. Follow your engine’s spec.
- Add a shutoff valve for storage and transport.
Controls
- Throttle must snap shut. Check it before every ride.
- Set the idle screw so the clutch does not drag at idle.
Source: youtube.com
First Start, Tuning, and Break-In
A smooth first run is a big win when you learn how to make a chainsaw mini bike.
First start
- Fill with fresh premix and prime the carb if needed.
- Choke on, two to four pulls, then choke off.
- Let it warm for 2–3 minutes.
Carb tuning
- Set low-speed needle for crisp takeoff without bog.
- Set high-speed needle for strong pull without a lean scream.
- Make small changes, 1/8 turn at a time.
Break-in
- Run short rides with easy throttle for the first tank.
- Check chain tension, hot bolts, and cable stretch after each ride.
Source: com.br
Common Mistakes and Easy Fixes
I made these mistakes so you don’t have to while learning how to make a chainsaw mini bike.
- Chain misalignment: Use a straightedge from clutch to rear sprocket. Shim the sprockets until the chain runs true.
- Gearing too tall: If starts feel weak or the clutch smells, go bigger on the rear sprocket or add a jackshaft.
- Weak brakes: Upgrade pads, add a larger rotor, or shorten the cable housing.
- Vibration: Add rubber mounts, balance the rear wheel, and secure all hardware with locknuts.
- Fuel issues: Old fuel or wrong mix ruins tune. Mix small fresh batches.
Source: youtube.com
Cost, Time, and Legal Checks
Budget and rules matter when you plan how to make a chainsaw mini bike.
Cost
- Engine from an old saw: low cost if you own one already.
- Clutch, sprockets, chain, and jackshaft: moderate cost.
- Wheels, brakes, throttle, and small parts: moderate to high.
- Expect a few weekends and a few hundred dollars total.
Time
- A careful first build takes 15–25 hours.
- Tuning and tweaks take another weekend.
Legal
- Most places limit where you can ride. Keep it off public roads unless it’s registered and compliant.
- Respect noise rules. A simple muffler shield helps.
Frequently Asked Questions of how to make a chainsaw mini bike
Is a chainsaw engine strong enough for a mini bike?
Yes, many 35–62 cc engines can move a small frame with the right gearing. Aim for 10:1 to 13:1 reduction for usable torque.
What clutch should I use?
Use a centrifugal clutch matched to your crankshaft size and rpm. A 10–12 tooth clutch for #35 chain is common for small builds.
Do I need a jackshaft?
Not always, but it helps reach ideal ratios without a giant rear sprocket. A jackshaft also gives better chain wrap and tension options.
How fast will it go?
With smart gearing and a healthy 50 cc, 18–22 mph is typical. Taller gearing can go faster, but you risk weak takeoff and clutch wear.
What fuel mix should I run?
Follow your engine’s specification, often 40:1 or 50:1 with quality two-stroke oil. Fresh fuel and a clean filter make a big difference.
How do I stop chain derailments?
Align both sprockets with a straightedge and set proper slack. Add a chain guide or guard for extra security.
Can I ride it on the street?
Usually no, unless it meets local road laws and equipment rules. Treat it as an off-road project unless you make it street legal.
Conclusion
You now know the full path for how to make a chainsaw mini bike, from layout and gearing to brakes and tuning. Keep it simple, gear it low, and double-check alignment. Small details make big wins here.
Start with a solid frame, a healthy clutch, and a safe brake. Take your time on the drive line and the throttle setup. When it fires up and pulls clean, the smile is instant.
If this helped, share your build, subscribe for more hands-on guides, or drop a question. I’m happy to help you turn your plan into a running mini bike.
