What Is a Tsumura Chainsaw Bar Mount? (Tail Pattern Chart)
A Tsumura chainsaw bar mount is the shape and layout of the bar’s tail, where it attaches to a saw. The right mount must match the saw’s studs, chain-tensioner pin, and oil outlet. Use Tsumura’s current fitment information for your exact saw model and bar part number; bar length alone cannot confirm fit.
Choosing a guide bar should feel straightforward: identify your saw, match the mount, then check the chain. The confusing part is that two bars can look similar and have the same length yet use different tail patterns. A mismatch may stop the bar from seating, keep the tensioner from working, or block oil from reaching the chain.
I treat the tail pattern as one part of a compatibility check, not as a stand-alone label. Below, you’ll find what the mount does, how to use a Tsumura bar mount chart, and what to verify before cutting.
Identify the Tsumura Mount Pattern and Verify Saw Compatibility
A bar mount, also called a tail pattern or mount pattern, is the set of shapes and openings at the back of the guide bar. Those features must match the saw’s mounting studs, chain adjuster, and oil outlet. Confirm the pattern using the exact saw model and Tsumura bar part number, then check the physical interfaces.
What the mount connects
The mount is the bar’s connection point to the powerhead. Its long slot fits over the bar studs, and a separate opening must accept the chain-tensioner pin. The oil holes in the bar tail must also line up with the saw’s oil outlet.
The chain adjuster moves the bar forward or backward to set chain tension. If its pin misses the bar’s adjuster hole, the bar may sit on the studs but cannot be adjusted as intended. A bar that appears to fit is not necessarily a compatible bar.
How to use a Tsumura bar mount chart
A fitment chart links a bar mount or part number to specific saw models. There is no safe reason to assume one chart entry fits every saw from a brand, or that a similar-looking tail uses the same pattern. Tsumura’s chart and the product’s part number are the references to check.
| What to check | Where to verify | Why it matters |
|---|---|---|
| Saw make and exact model | Saw label and operator’s manual | Similar models may use different fittings |
| Tsumura mount code or bar part number | Current Tsumura fitment information or bar label | Identifies the intended bar configuration |
| Stud slot and bar studs | Compare the bar tail and saw | The bar must seat freely on both studs |
| Adjuster hole and tensioner pin | Inspect the saw and bar together | The pin must engage so tension can be set |
| Oil holes and oil outlet | Inspect alignment at the tail | The chain needs oil while it runs |
If a chart lists several bar options, match the full saw model, not just the brand or engine size. If the chart is unclear, confirm the part number with the seller or Tsumura before buying.
Mount fit is not the whole chain setup
A correct tail pattern does not prove that the bar and chain match. Check the bar’s stamped pitch and gauge, then use a chain with the same specifications and the required number of drive links. Also check that the saw’s drive sprocket is compatible with that chain setup.
Pitch is the chain-size specification used for the chain and sprocket interface. Gauge is the thickness of the chain’s drive links where they sit in the bar groove. Drive-link count is the number of links that travel around the bar. For example, 3/8-inch low-profile pitch and .050-inch gauge are possible specifications, not universal Tsumura requirements.
Use the saw maker’s approved bar-length range and application guidance. Engine displacement alone does not establish which bar length is safe or suitable. Key takeaway: confirm the mount, chain dimensions, and saw guidance as separate checks.
Set Up the Bar and Chain for Safe Field Cutting
Setting up a compatible bar means more than tightening the nuts. The bar must seat correctly, the tensioner must engage, and the oil holes must deliver oil to the chain. Follow the saw manual for the exact procedure, tension, and fastener instructions; there is no single setting that applies to every saw and bar combination.
Before you fit the bar
Identify the saw’s exact model and note the markings on the current bar and chain. Compare them with the proposed Tsumura part number and the current fitment chart. If any specification is missing or does not agree, pause and confirm it rather than guessing.
For service, stop the engine and let the saw cool. Engage the chain brake, then disconnect the spark-plug lead or battery as directed by the manual. Wear suitable protective equipment when handling the chain; its cutters can injure you even when the saw is off.
Fit and check each interface
Remove the old bar and chain as described in the saw manual. Clean the mounting area enough to see the studs, adjuster pin, and oil outlet. Fit the new bar over the studs without forcing it, and check that the tensioner pin enters its hole.
Before installing the chain, confirm that the bar’s oil holes align with the saw’s oil outlet. Then install the specified chain in the cutting direction shown in the manual or on the saw. Adjust tension and tighten the bar nuts using the saw maker’s instructions. Do not apply a generic torque value; the required procedure depends on the saw.
| Check after assembly | What a correct result looks like | If it does not |
|---|---|---|
| Bar seating | Bar sits flat and moves as intended during adjustment | Stop and recheck mount compatibility |
| Tensioner engagement | Adjuster moves the bar to set tension | Do not force the adjuster |
| Chain fit | Chain matches the stamped pitch, gauge, and link count | Confirm the chain and sprocket specifications |
| Oil delivery | Oil reaches the chain and bar as described in the manual | Clean and check the oil path before use |
Verify oiling before cutting
A blocked or misaligned oil path can leave the chain without the lubrication it needs. Clean the oil holes and mounting area, then check oil flow using the method in the saw manual. Oil type and delivery settings vary by saw; follow its instructions rather than changing a setting based on a general rule.
If the bar seems to fit but the tensioner pin or oil holes do not line up, do not modify the tail, force the fit, or operate the saw. Poor tensioning or oiling can damage the bar and chain and may contribute to chain derailment or loss of control. Key takeaway: no cutting until the bar seats, adjusts, and oils correctly.
Inspect, Maintain, and Sharpen the Bar-and-Chain System
The bar and chain wear together, so checking only the cutters can miss problems. Inspect the bar groove, rails, oil holes, chain tension, and drive area as part of routine service. Follow the saw and bar makers’ guidance for sharpening, wear limits, and replacement; exact limits depend on the parts.
Checks after use
Stop the saw, let it cool, and follow the manual’s shutdown steps before inspection. Look for debris in the bar groove and oil holes, uneven wear on the rails, damage at the bar tail, or a chain that no longer holds proper tension. Clean the groove and oil holes with suitable tools, taking care around sharp cutters.
Keep the chain sharp and correctly tensioned according to the saw manual. A dull or poorly adjusted chain can make cutting harder and put extra strain on the system. If the bar is damaged, the chain will not tension properly, or oil delivery remains uncertain, correct the problem before using the saw again.
Real-world fitment checks
A useful way to avoid a wrong purchase is to compare the old bar’s part number and markings with the new bar’s fitment data. For instance, if a replacement has the right length but the adjuster opening sits in a different position, the length does not make it a match. Check the exact model and mount details before removing the old bar.
Another common check is made during a trial fit. If the studs accept the slot but the tensioner pin does not enter the hole, the interfaces are not compatible. Likewise, a bar that seats and adjusts still needs correctly aligned oil holes. These are practical fitment checks, not proof that any specific Tsumura part fits a particular saw. Key takeaway: verify all interfaces, not just the one that looks right.
Clean, Protect, and Store the Saw and Guide Bar
Clean storage helps keep the bar mount and oil path ready for the next use. Remove sawdust and oil residue from the bar groove and tail, and inspect the parts before putting them away. Store and protect the chain as the saw maker directs, and address damage or oiling problems before the next cutting job.
After use, stop the saw and let it cool before cleaning. Clear packed debris from the groove and oil holes, and check the mounting area for damage. If you remove the bar, keep its part number and specifications available so you can confirm them later.
Do not use a damaged or altered mount to make a bar fit. Do not reshape the tail or enlarge its openings. A change can affect how the bar seats, how the adjuster works, or whether the chain receives oil. Next step: use the exact saw model and bar part number to verify fit before installation.
Frequently Asked Questions
These quick answers cover the most common Tsumura bar mount questions. For any specific fitment, use the current Tsumura information for the bar part number and exact saw model, then confirm the chain and oiling details in the saw manual.
Is a Tsumura bar mount the same as bar length?
No. Bar length describes the cutting length, while the mount describes how the bar attaches to the saw. A bar of the correct length can still have the wrong stud slot, adjuster opening, or oil-hole layout.
How do I find the correct Tsumura mount for my chainsaw?
Write down the saw’s make and exact model, then check Tsumura’s current fitment chart or the bar’s part number. Confirm the stud slot, tensioner hole, and oil holes against the saw before use.
Can I choose a mount by chainsaw brand alone?
No. A brand may sell saws with different mounting arrangements. Use the exact model and verify the bar part number or mount code; do not rely on brand, appearance, or engine size alone.
Will a longer bar fit if the mount is correct?
Not necessarily. The mount is only one part of compatibility. Check the saw maker’s approved bar-length range, and separately match chain pitch, gauge, and drive-link count.
What if the bar fits over the studs but will not tension?
Stop and check whether the adjuster pin enters the bar’s adjustment hole. If it does not engage or the bar binds, do not force it or run the saw. Recheck the mount and part number.
How can I tell if the bar’s oil holes line up?
With the saw off and prepared for service as its manual directs, inspect the bar tail against the saw’s oil outlet. The oil path must be open and aligned; confirm oil delivery using the manual’s test method.
Can I enlarge or reshape a Tsumura bar tail?
No. Do not modify the mount to make it fit. Altering the tail can affect seating, tensioning, and lubrication. Choose a bar specified for the exact saw model instead.
Are chain pitch and gauge part of the mount pattern?
No. They are separate chain-and-bar specifications. Match the bar’s stamped pitch and gauge to the chain and sprocket, and use the required drive-link count.
Is there one torque value for all bar nuts?
No. Follow the saw’s operator’s manual for tightening instructions. A general torque value should not be applied to every saw and bar combination.
What should I do if I cannot confirm the mount code?
Do not guess or operate the saw with an unverified bar. Check the bar part number and current fitment information, then ask the saw or bar seller to confirm compatibility for the exact model.
(This article was written by one of our staff writers, Evan Bradley. Visit our Meet the Team page.)
