STIHL 066 Magnum Chainsaw (Specs & Bar Chart)
The STIHL 066 Magnum is a 91.6 cc professional saw rated at about 5.2 kW (7.1 hp), with a dry powerhead weight near 7.9 kg (17.4 lb). Common bar lengths run from 20 to 36 inches, but fit depends on the saw’s mount, sprocket, chain pitch, gauge, and drive-link count. Check those before buying.
If you have several listings open, start with the parts that must match, not the longest bar a seller says will fit. Older 066 saws may have different parts or replacement components, so the model name alone cannot confirm a chain or bar order. A shorter, correctly matched setup is often easier to handle; no bar choice removes the need for regular sharpening, tension checks, and oiling.
I treat a used 066 as an individual saw, not just a spec sheet. The model’s published figures help set expectations, but the installed sprocket, bar mount, and chain determine what you can actually fit. For a low-hassle purchase, choose a sound saw with a verified setup and readily identified replacement parts. Have a qualified saw technician inspect an uncertain or modified machine.
STIHL 066 Magnum specifications
These figures provide a baseline for comparing an 066 listing with the machine in front of you. They describe the powerhead, not a complete saw with bar, chain, fuel, or oil. Model year and installed parts can affect service details, so confirm the exact manual and markings before ordering parts or adjusting the saw.
| Specification | Published reference |
|---|---|
| Engine displacement | 91.6 cm³ |
| Engine type | Single-cylinder, air-cooled, two-stroke |
| Output | Approximately 5.2 kW (7.1 hp) |
| Powerhead weight | Approximately 7.9 kg (17.4 lb), dry, without bar or chain |
| Common bar range | 20–36 in., depending on setup and work |
| Common chain pitch | 3/8 in.; some configurations use .404 in. |
| Common chain gauges | .050, .058, or .063 in., depending on parts |
| Fuel mix | 50:1 with suitable STIHL two-stroke oil, subject to the specific manual |
The powerhead weight is not the weight you will hold while cutting. A bar, chain, fuel, and oil add to it, and a longer bar changes balance and leverage. Compare complete saw weights only when the listings use the same measurement basis.
The 066 Magnum badge does not establish a different fuel ratio. Use fresh unleaded gasoline mixed 50:1 with suitable STIHL two-stroke oil, and follow the manual for the particular saw and oil. Do not run straight gasoline or an unverified mix: inadequate lubrication can damage the engine.
Bar and chain chart: choosing a compatible setup
A bar chart is a starting point, not a promise that every 066 accepts every listed length. Bar length means the cutting length of the guide bar; chain pitch and gauge describe the chain’s fit to the sprocket and bar groove. Confirm all fit details on the saw and replacement parts before ordering.
| Bar length | Typical use | Check before purchase |
|---|---|---|
| 20–25 in. | General felling and bucking; more compact handling than a longer bar | Bar mount, pitch, gauge, sprocket, and drive-link count |
| 28–36 in. | Larger timber and cuts that need more reach | Matching bar, chain, sprocket, machine condition, and operator control |
The 20–25-inch range is a practical place to start for many general felling and bucking jobs. A shorter bar can be easier to manage, but it still needs to suit the cut and operator. The 28–36-inch range can provide more reach and cutting capacity, but it is not automatically better because the engine is large. The wood, cutting position, control, and exact parts matter.
Before buying a bar and chain, check these four items:
- Bar mount: The bar’s mounting pattern must fit the saw. Do not assume a listing marked “for STIHL” fits the 066.
- Pitch: The chain pitch must match the drive sprocket and bar nose. Common 066 setups use 3/8-inch pitch; some use .404-inch.
- Gauge: The chain’s drive-link thickness must match the bar groove. Common gauges include .050, .058, and .063 inch, but verify yours.
- Drive links: The required count depends on the specific bar and setup. Read the bar marking or count the existing chain’s drive links. Bar length alone is not enough.
Read the bar stamp and sprocket marking where possible. If either is missing or unclear, take the bar and chain details to a qualified dealer or saw shop. A chain that looks close can still be the wrong pitch or gauge. Never force a mismatched chain onto the bar or sprocket.
Setup examples for common jobs
These are selection examples, not fixed factory configurations. Each assumes the bar, chain, and sprocket have been checked as a set. I use this kind of comparison when a buyer is choosing between two listings: it brings the decision back to the work and parts, instead of relying on the “Magnum” label or a seller’s broad fit claim.
| Work scenario | Starting point to assess | What could change the choice |
|---|---|---|
| General ground-based bucking | 20–25 in. bar | Log size, access, operator control, and confirmed parts |
| Felling or bucking larger timber | 28 in. or longer, if the setup is approved and controlled | Tree size, lean, site hazards, saw condition, and operator skill |
| Saw has an unknown replacement bar | Do not order from length alone | Identify mount, pitch, gauge, sprocket, and drive-link count first |
For example, a buyer comparing a 24-inch setup with a 32-inch setup should not decide by displacement alone. Ask which cuts the saw must make, whether the longer bar is correctly matched, and whether the operator can maintain control in the planned cutting position. If those facts are unknown, verify them before purchase.
In my equipment evaluations, the most useful “case study” is often a parts check on an older saw: a model label identifies the family, while the bar stamp and sprocket reveal the installed system. That check can prevent an otherwise avoidable chain-order mistake. It is not a substitute for inspection of the saw or its service history.
Equipment setup, cutting, and safety checks
Safe use starts with a sound saw and a planned cut, not a bar chart. A chain saw can cause severe injury, and the 066’s power does not compensate for poor control or a damaged part. Before work, inspect the machine, assess the site, and use the personal protective equipment and procedures required for your job.
Wear a helmet, eye and face protection, hearing protection, chainsaw chaps, gloves, and protective boots. Check applicable ANSI Z133 requirements for tree work and OSHA rules where they govern the job. Plan escape routes and look for lean, deadwood, overhead hazards, poor footing, bystanders, and property that could be struck.
Before starting, inspect the chain brake, throttle lockout, chain catcher, controls, chain tension, bar rails, fasteners, and fuel and oil caps. Check that the chain is sharp, undamaged, and tensioned as directed in the manual. Use the manufacturer’s starting procedure on firm ground, with the chain clear of people and objects. Do not drop-start the saw.
At idle, the chain should remain stationary. Check that the throttle responds and the chain brake works as intended. Confirm chain-oil delivery before cutting, using the manual’s procedure. Keep two hands on the saw and use a stable stance. Keep the bar nose clear of wood and other objects: contact at the upper quadrant of the nose can cause rotational kickback, driving the bar up and back toward you. Do not cut above shoulder height or treat the chain brake as a replacement for safe technique.
Use a bar length suited to the cut and your control. If a tree shifts unexpectedly, a kerf closes, or the bar binds, stop and reassess instead of forcing the saw. A dull, loose, damaged, or mismatched chain is a reason to stop and correct the setup before continuing.
Maintenance, chain sharpening, and carburetor checks
Routine checks help you spot problems before they damage the saw or disrupt a job. The exact service intervals and settings depend on the saw’s manual and condition. Do not use a general chart as a replacement for the correct model-specific instructions, especially for chain sharpening, carburetor tuning, or maximum engine speed.
The automatic chain-oiling system is adjustable. Use proper bar-and-chain oil and confirm delivery before cutting; oil flow needs can change with temperature, oil, bar, and pump setting. There is no single dependable flow-rate or oil-viscosity figure for every setup. If oil delivery seems weak, inspect the oil supply and passages and consult the manual rather than assuming a pump setting.
A .025-inch (0.65 mm) depth-gauge setting is common for compatible standard chains, but the chain maker’s specification takes priority. Depth gauges control how much wood each cutter can take. Incorrect filing can affect cutting behavior, so use the chain maker’s sharpening instructions and a suitable gauge. Replace a damaged chain rather than trying to restore unsafe parts.
About 2,500 rpm at idle and up to 13,000 rpm maximum are reference figures, not tuning targets for every 066. Verify the exact service specification and use a tachometer when checking engine speed. Do not tune by ear or exceed the specified limit. If the saw will not idle steadily, runs poorly, or has an uncertain carburetor setting, have a qualified technician diagnose it.
After cutting, set the chain brake for handling, shut off the engine, and let the saw cool before refueling or maintenance. Clean debris from the cover, brake area, bar groove, and oil passages. Inspect the bar rails and chain for wear or damage, and retension only as directed. Store the saw safely and follow the manual’s guidance for fuel during storage and seasonal use; do not leave an unverified fuel mix in the saw.
Frequently asked questions
These short answers address the fit and specification checks that most often affect an 066 purchase. Use them as a final checklist, then verify the saw’s own markings and manual. If parts do not match or the machine’s history is unclear, pause the order and ask a qualified STIHL dealer or saw technician to identify the setup.
How many cc is the STIHL 066 Magnum?
It has a 91.6 cm³ engine.
How much power does the 066 Magnum make?
Published output is approximately 5.2 kW, or 7.1 hp.
What is the 066 powerhead weight?
Approximately 7.9 kg (17.4 lb), dry and without the bar or chain. A complete saw weighs more.
What bar lengths are common on an 066?
Common lengths range from 20 to 36 inches. Confirm that the specific bar, chain, mount, and sprocket match.
Can I fit a 36-inch bar?
Some setups use bars in this range, but length alone does not confirm fit or suitability. Check the complete system and consider the cut and operator control.
Does every 066 use 3/8-inch chain?
No. Many use 3/8-inch chain, while some configurations use .404-inch pitch. Check the sprocket and bar.
What chain gauge should I buy?
Common gauges include .050, .058, and .063 inch. Match the chain gauge to the bar groove; do not guess.
How many drive links does my chain need?
There is no single count for every bar. Read the bar marking or count the drive links on the correct existing chain.
What fuel mix does the 066 use?
The reference mix is fresh unleaded gasoline at 50:1 with suitable STIHL two-stroke oil. Follow the manual for the specific saw and oil.
What should I check before buying a used 066?
Confirm the model and condition, then identify the bar mount, sprocket pitch, chain gauge, bar marking, and drive-link count. Check safety parts and ask for a qualified inspection if the saw has unknown modifications.
(This article was written by one of our staff writers, Marcus Thorne. Visit our Meet the Team page.)
