Stihl model · engine series 1143
MS 251 45.6 cc
- Chain
- .325″ · .050–.063″
- Recommended bar
- 14–18″
- Mount
- 3005 / A074
MS 251 chain size: .325″ · .050–.063″, 3005-mount bar. Typical STIHL drive-link counts for .325" chain: 16″ = 62, 18″ = 68. Count the links on your old chain or read the bar stamp before ordering.
Model displacement · family chain/bar fitment. Details & confidence ↓
See also: MS 231 · 241 · 251 family specs · chain and file size guide · part number lookup
Parts diagrams (14)
Browse saved diagrams & other models ↗276 parts entries · catalogue coverage: MS 231, MS 231 C, MS 251, MS 251 C. Check the sheet’s variant and serial notes.
Model & family fitment specs
Displacement is specific to the MS 251 roster record. Chain, bar and mount are the published family fitment for engine series 1143; confirm the pitch, gauge and drive-link count stamped on your installed bar before ordering.
Chain, bar and mount: family research from STIHL product pages and parts catalogues, dealer fiche and collector records. Checked Jul 2026. How we check fitment
Chains & bars that fit the MS 251
Pitch & gauge .325″ · .050–.063″ · recommended bar 14–18″ · bar mount 3005 / A074 · round file 3/16" (4.8 mm)
Chain & bar by length
| Bar | Drive links | Shop |
|---|---|---|
| 16″ | 62 DL | Chain .050″ →Chain .063″ → Bar · 3005 → |
| 18″ | 68 DL | Chain .050″ →Chain .063″ → Bar · 3005 → |
Drive-link counts come from STIHL's saw-chain selection chart and depend on the bar mount as well as length. Pick the chain link that matches the gauge stamped on your bar. Bar searches include mount 3005 / A074; still confirm the mount stamp, pitch, gauge and drive-link count on your installed bar before ordering.
Drive-link counts: STIHL 2025 US catalog, saw chain selection, pp. 166-167; Oregon chain fit guide, STIHL section. Checked Nov 2026. How we check fitment
Files, oil & sharpening
Suggested match: Oregon 95VPX or 20LPX (.050″) · 21LPX (.058″) · 22LPX (.063″). Match the gauge and confirm the drive-link count for your exact bar 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.
Some links earn us a commission. It never changes the specs or what we recommend.
Service & tuning
Factory tuning settings
| Idle speed | 2,800 rpm |
| Max speed | 13,000 rpm |
| H screw (high speed) | 3/4 turn |
| Confidence | sourced |
Screw figures are turns open from lightly seated. 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 251
45.6 cc
Production, market and rarity are specific to this model’s roster record.
Related models in series 1143
Shared engine-family membership does not establish parts interchangeability.
Data confidence
Chain, bar, mount and displacement confidence comes from the shared MS 231 · 241 · 251 family research.
Something wrong or missing for the MS 251? Report a correction →