Poulan 3400 Chain Replacement (Fitment Guide)
For a common Poulan 3400 setup with a 20-inch bar, the chain is often 3/8-inch pitch, .050-inch gauge, and 72 drive links. Treat that as a starting point, not a guarantee. Before buying, check the installed bar, count the old chain’s drive links, and confirm the drive sprocket matches. The bar, sprocket, or chain may have been changed.
Older saws like the 3400 can still be ready for work, but replacement parts may not match what left the factory. In the shop, I treat the markings on the parts actually fitted to the saw as more useful than a model name alone. A wrong chain can bind, sit poorly in the groove, or come off.
The checks below help you identify the chain, fit it safely, and verify it before cutting. If the parts disagree or their markings are unreadable, pause and identify the bar and sprocket rather than forcing a fit.
Poulan 3400 chain size: the fitment starting point
Chain fitment means matching three measurements: pitch, gauge, and drive-link count. A common 20-inch setup for a Poulan 3400 is 3/8-inch pitch, .050-inch gauge, and 72 drive links. Because bars and sprockets may have been replaced, verify all three on the saw before ordering.
| Measurement | Common 20-inch setup | What to verify |
|---|---|---|
| Pitch | 3/8 inch | Match the chain to the drive sprocket and bar nose sprocket |
| Gauge | .050 inch | Match the thickness of the chain’s drive links to the bar groove |
| Drive links | 72 | Count the links that sit inside the bar groove |
| Bar length | 20 inches | Use as a cross-check, not as the chain identifier |
Pitch is the spacing used by the chain and sprocket teeth. Gauge is the thickness of the drive links, the small projections that ride in the bar groove. Drive-link count is the number of those projections around the full chain. All three must match; bar length alone is not enough to choose a chain.
Start by reading the bar’s stamp, often near the mounting end. It may list pitch, gauge, and a chain-link count or an equivalent chain specification. If the old chain is still present, count its drive links. Do not count the sharp cutters.
If the stamp and old chain disagree, do not choose whichever number seems more likely. The saw may have a replacement bar, a different sprocket, or a past conversion. The next step is to check those parts as a set.
Check the bar, chain, and sprocket together
The bar is the long guide that supports the chain. Its groove must suit the chain’s gauge, and its sprocket must suit the chain’s pitch. Checking these parts together prevents a common mistake: ordering a chain that matches one component but not the complete setup.
Inspect the bar stamp and the drive sprocket markings, if present. The drive sprocket is the toothed wheel that moves the chain at the saw’s powerhead. Its pitch must match the chain. Also check the bar nose sprocket, if fitted, and confirm that the bar’s mounting pattern and oil holes suit the saw if you are replacing the bar too.
Use this quick decision table:
| What you find | Best next step |
|---|---|
| Bar stamp and chain agree; sprocket pitch agrees | Order a chain matching all three specifications |
| Bar stamp is missing, but the old chain is intact | Count drive links and identify pitch and gauge from reliable chain or bar markings |
| Chain will not sit in the bar groove | Stop; recheck gauge and bar condition |
| Chain does not seat smoothly on the drive sprocket | Stop; recheck pitch and sprocket condition |
| Bar, chain, and sprocket markings conflict | Identify the installed parts before buying |
A worn sprocket can damage or wear a new chain more quickly, so inspect its teeth before fitting a replacement. Replace a worn sprocket rather than running a new chain on it. If the groove is damaged, the bar is bent, or the oil holes do not line up with the saw, address that issue before fitting a new chain.
Fit the replacement chain safely
A chain should be fitted cold, with the engine stopped and the spark-plug lead disconnected. This prevents an accidental start while your hands are near the cutters and sprocket. Wear gloves while handling the chain, and use the saw’s manual for the correct clutch-cover and chain-brake procedure.
Before working, wear eye and hearing protection, chainsaw chaps, gloves, and boots. Check the chain brake, throttle trigger and interlock, chain catcher, handles, bar, and chain. Do not operate the saw if a safety part is damaged or does not work.
Follow these steps:
- Place the saw on a stable surface. Stop the engine and disconnect the spark-plug lead.
- Release the chain brake only as directed by the saw’s procedure. On some designs, removing the clutch cover with the brake engaged can cause trouble. Do not force the cover.
- Loosen the bar nuts and remove the clutch cover. Note how the bar and tension adjuster fit together.
- Place the chain around the drive sprocket and into the bar groove. Along the top edge of the bar, the cutters must point toward the bar tip.
- Seat every drive link fully in the groove and confirm the chain engages the sprocket. If it does not, stop and recheck the pitch and gauge.
- Refit the cover loosely. Lift the bar nose, then adjust the tension until the chain sits in the groove but can still be pulled around by hand with a gloved hand.
- Keep the bar nose raised while tightening the bar nuts. Recheck tension and make sure the chain moves freely by hand.
Do not guess a torque value for the bar nuts. Use a value only if it is specified for the fasteners in the correct manual. If the adjuster reaches its limit before the chain is tensioned, or the chain binds, do not force it. Recheck the parts and how the chain is seated.
First start and checks after installation
A correctly fitted chain still needs a safe start and a lubrication check. Follow the saw’s own starting procedure and chain-oil test. Stop immediately if the chain binds, rides out of the groove, or fails to receive oil; do not try to correct a fit problem by running the saw at higher throttle.
Start on stable ground with the chain brake engaged, as the saw’s procedure directs. Disengage the brake only when you are ready to cut. Hold the saw with both hands, keep secure footing, and keep the bar nose clear of objects. The bar tip can cause kickback if it contacts wood or another object.
Check chain lubrication using the method in the saw manual. If the chain is not being oiled, stop and inspect the oil supply, bar oil holes, and passages. Do not cut with a dry chain. After the first cuts, stop the saw, engage the brake, and check tension again. A new chain can need adjustment as it settles into use.
Common fitment problems and practical examples
These examples show how to reason through mismatched parts; they are not proof that every 3400 has the same setup. I use the same method at the bench: identify each installed part, compare its markings, then fit only a chain that agrees with the complete setup.
Example: 20-inch bar, markings agree. The bar is stamped for 3/8-inch pitch and .050-inch gauge, the old chain has 72 drive links, and the sprocket matches the pitch. That is consistent with the common 20-inch specification. Confirm the new chain’s package lists all three values before installing it.
Example: 20-inch bar, but the old chain has a different link count. Do not assume the old chain is wrong just because 72 is common. Check the bar stamp, chain fit, and sprocket. The saw may have a different replacement bar or setup.
Example: the chain seems nearly right but will not move smoothly. Stop. A gauge that is too narrow may not be held properly in the groove, while a pitch mismatch may not seat on the sprocket. Do not force the tension adjuster or test the saw at throttle.
After work, clean chips from the clutch cover, bar groove, and oiler outlet. Check the chain and bar for damage, and store the chain protected from corrosion with the bar cover fitted. For seasonal storage, follow the manual’s fuel instructions. Keep fuel and bar oil separate, and use the specified products.
Frequently asked questions
These quick answers cover the fitment choices that most often delay a replacement. When the saw’s parts do not agree with the common setup, use the markings and condition of the installed bar and sprocket to identify the correct chain rather than relying on a general model listing.
What size chain does a Poulan 3400 use?
A common setup with a 20-inch bar is 3/8-inch pitch, .050-inch gauge, and 72 drive links. Verify the bar, sprocket, and chain before buying.
Will any 20-inch chain fit the Poulan 3400?
No. Bar length does not identify pitch, gauge, or drive-link count. The chain must match all three, and its pitch must match the sprocket.
How do I count drive links?
Count the projections on the chain’s inside edge that sit in the bar groove. Do not count the cutters or count the links by the bar’s length.
Can I use a .058-inch gauge chain instead of .050-inch?
Only if the installed bar groove is made for .058-inch drive links and the other specifications also match. Do not substitute gauges by guesswork.
Can I use a different drive-link count on a 20-inch bar?
A different count may suit a different bar or setup, but it must fit the installed bar and sprocket with proper tension adjustment. Confirm the bar’s specification first.
What if the bar has no readable stamp?
Count the old chain’s drive links and identify its pitch and gauge from reliable chain markings. If those details cannot be confirmed, identify the bar and sprocket before ordering.
Which way should the cutters face?
Along the top edge of the bar, the cutting edges should point toward the bar tip. Check this before refitting the cover.
Why does my replacement chain bind?
Possible causes include a pitch mismatch, incorrect gauge, poor seating, damage, or excessive tension. Stop and inspect; never force the chain around or run it to see if it frees up.
What chain filing angle or file size should I use?
Use the chain manufacturer’s instructions for the exact chain fitted. Do not select a file size or sharpening angle based only on the saw model.
What fuel mix should I use in a Poulan 3400?
Use the ratio stated on the saw’s label or in the correct manual. Do not assume a modern 50:1 mix or apply a generic carburetor setting.
Before heading out, confirm the chain’s pitch, gauge, and drive-link count; check that it moves freely and receives oil; then recheck tension after the first cuts. If any part does not agree, stop and identify it before operating.
(This article was written by one of our staff writers, David Hensley. Visit our Meet the Team page.)
