Bore, stroke, displacement and compression for all 10 Honda E-series engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 81.9–97.6 ci |
|---|---|
| Cylinders | 4 |
| Bore | 2.913" |
| Stroke | 3.071–3.661" |
| Compression | 7.9–9.2:1 |
| Advertised power | 58–91 hp |
| Years | 1975–1987 |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| EF1 | 97.6 ci | 2.9134" × 3.6614" | 8:1 | — |
| EF1 | 97.6 ci | 2.9134" × 3.6614" | 8:1 | 68 |
| ED EM EW | 90.8 ci | 2.9134" × 3.4055" | — | — |
| ED | 90.8 ci | 2.9134" × 3.4055" | 7.9:1 | — |
| EM | 90.8 ci | 2.9134" × 3.4055" | 8.8:1 | 67 |
| EW1 | 90.8 ci | 2.9134" × 3.4055" | 9.2:1 | 76 |
| EW | 90.8 ci | 2.9134" × 3.4055" | 9.2:1 | 58 |
| EW3/EW4 | 90.8 ci | 2.9134" × 3.4055" | 8.7:1 | 91 |
| EV1 | 81.9 ci | 2.9134" × 3.0714" | — | — |
| EV1 | 81.9 ci | 2.9134" × 3.0714" | — | 60 |
Every engine here shares a 2.9134" bore; displacement varies by stroke alone, which is the signature of a family built on one block with different cranks.
All are undersquare — stroke larger than bore, favouring torque low in the range.
Each engine page carries rod ratio, mean piston speed, bore/stroke character and cylinder head specs where published, and links into the calculators with its dimensions already filled in.