Stihl model · engine series 1144

MS 661 R 91.1 cc

Chain: 3/8″ · .063″ · .404″ on long bars
Recommended bar: 20–36″
Mount: 3003 / D025

Model displacement · family chain/bar fitment. Details & confidence ↓

Parts diagrams (26)

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482 parts entries · catalogue coverage: MS 661. Check the sheet’s variant and serial notes.

Model & family fitment specs

Actual displacement91.1 cc

Guide bar20–36″

Chain3/8″ · .063″ · .404″ on long bars

Bar mount3003 / D025

Displacement is specific to the MS 661 R roster record. Chain, bar and mount are the published family fitment for engine series 1144; confirm the pitch, gauge and drive-link count stamped on your installed bar before ordering.

displacement · verifiedbar real-world · sourcedbar mount · sourcedchain · sourceddates · verifiedvariants · verified

Chains & bars that fit the MS 661 R

Pitch & gauge 3/8″ · .063″ · .404″ on long bars · recommended bar 20–36″ · bar mount 3003 / D025 · round file 7/32" (5.5 mm)

Replacement chain → Guide bar · 3003 →

Chain & bar by length

Bar	Drive links	Shop
20″	72 DL	Chain → Bar · 3003 →
22″	76 DL	Chain → Bar · 3003 →
25″	84 DL	Chain → Bar · 3003 →
28″	91 DL	Chain → Bar · 3003 →
32″	105 DL	Chain → Bar · 3003 →
36″	114 DL	Chain → Bar · 3003 →

Drive-link counts come from STIHL's saw-chain catalog. Bar searches include mount 3003 / D025; still confirm the mount stamp, pitch, gauge and drive-link count on your installed bar before ordering.

Files, oil & sharpening

Round file 7/32" (5.5 mm) → Bar & chain oil → 2-in-1 sharpener →

Suggested match: Oregon 72/73/75 EXL. Confirm the drive-link count for your exact bar length before ordering. These are equivalent aftermarket (Oregon) chains, not genuine STIHL chain — STIHL sells its own chain through its dealer network, and we're not affiliated with STIHL. New to fitment? See the bar-mount identification guide and chain & cutter guide.

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Service & tuning

Factory tuning settings

Idle speed	2,800 rpm
Max speed	13,500 rpm
Confidence	sourced

Set the final mixture by ear and tachometer against the machine in front of you — running a two-stroke lean to hit a published number is how pistons get scored.

About the MS 661 R

Production2014→

MarketGlobal

RarityCurrent

Engine family1144

Family era2014→now

Wrap handle, non-electronic

Production, market and rarity are specific to this model’s roster record.

Shared engine-family membership does not establish parts interchangeability.

Data confidence

Chain, bar, mount and displacement confidence comes from the shared MS 661 (MAGNUM®) family research.