BSA D1
Real ownership data from 131 UK D1 motorcycles — mileage, MOT pass rates and the faults that actually come up, taken from DVSA test records rather than opinion.
Most common D1 problems
Ranked by how often each fault appears in this model's MOT history.
| Fault | Severity | Share of faults |
|---|---|---|
| Lights and indicators | fail | 12.8% |
| Brakes | fail | 11% |
| Other | fail | 7% |
| Tyres | fail | 5.1% |
| Steering and head bearings | fail | 4.8% |
| Suspension | major | 2.9% |
| Electrical | fail | 2.9% |
| Chain and sprockets | fail | 2.2% |
Advisories (wear noted but not failed) are excluded above; the most common is suspension.
D1 mileage and reliability by year
Use this to judge whether a specific bike is high or low mileage for its age.
| Year | Examples | Median mileage | Miles/year | First-time pass |
|---|---|---|---|---|
| 1959 | 5 | 19,526 mi | 220 | 92.31% |
| 1955 | 11 | 12,426 mi | 68 | 100% |
| 1954 | 5 | 25,340 mi | 10 | 95.24% |
| 1953 | 13 | 10,868 mi | 1,140 | 87.5% |
| 1952 | 15 | 9,780 mi | 94 | 86% |
| 1951 | 10 | 11,124 mi | 68 | 87.18% |
| 1950 | 11 | 24,003 mi | 361 | 83.33% |
| 1949 | 5 | 20,256 mi | 29 | 80% |
D1 questions, answered with data
What are the most common problems with the BSA D1?
Across 131 UK examples, the most frequently recorded MOT faults are lights and indicators (12.8% of all recorded faults), brakes (11% of all recorded faults), other (7% of all recorded faults).
What is average mileage for a BSA D1?
The median BSA D1 in the UK has covered 11,124 miles, and typically rides about 83 miles a year. Half of all examples fall between 1,675 and 25,446 miles.
Is the BSA D1 reliable?
88.35% of BSA D1 MOT tests are passed first time, with an average of 0.64 faults recorded per test. This is measured from DVSA MOT records, not owner opinion.
Based on DVSA MOT test records for 131 BSA D1 motorcycles registered in Great Britain and Northern Ireland. Contains public sector information licensed under the Open Government Licence v3.0.