Yamaha Unknown (1983)
1983 Yamaha Unknown
CarHunch analysed 33,169 real MOT records for the 1983 Yamaha Unknown. This breakdown of actual test outcomes — pass rates, defect profiles, mileage data — isn't published anywhere else.
These 1983 Yamahas pass their MOTs at 70%, which is 10 percentage points below the UK average of 80%—a meaningful gap that suggests reliability concerns. The genuinely positive news is that dangerous defects are rare, affecting just 0.1% of vehicles, so safety isn't the issue here.
At a median mileage of 14,470 miles, these machines are lightly used for their age, yet they're still struggling to pass. The zero average failures and advisories recorded is unusual and likely reflects either incomplete testing data or the specific nature of motorcycle MOTs, so treat the pass rate as your real guide—if you're buying one, factor in above-average maintenance costs and get a pre-purchase inspection from someone who knows these bikes well.
What to check before buying a 1983 Yamaha Unknown
Practical pre-purchase checks for this age and model.
- 📋 Check the full MOT history. Look for recurring advisories — slow-building issues like corrosion or brake wear patterns show up years before they become failures. Enter the reg below for a full AI analysis.
- 🔍 Inspect for corrosion in person. Brake pipes, sills, subframes, and chassis legs. Surface rust is normal at this age; structural rust is a serious problem that's expensive to fix and can fail an MOT.
- 🛞 Check tyres and brakes. The most common advisory items at this age. Budget for replacement if they're near the limit — factor this into your offer price.
- 📄 Run an HPI check. The MOT history won't show outstanding finance, insurance write-offs, or stolen status — an HPI check will.
Before you buy a Yamaha Unknown
MOT history is one piece of the puzzle. These checks can reveal what CarHunch can't.
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Pass Rate by Fuel Type
| Fuel type | Vehicles | Pass rate | Avg failures |
|---|---|---|---|
| Petrol (100%) | 33,158 | 0.7% | 0 |
| Diesel (0%) | 6 | 0% | 0 |
| Other (0%) | 5 | 95% | 0.2 |
Mileage Distribution
Most 1983 Yamaha Unknown vehicles sit in the blue band. If the car you're looking at is outside it, it's either unusually low or high mileage for its age.
Half of all 1983 Yamaha Unknown vehicles fall between 5,910 and 23,269 miles.
1983 Yamaha Unknown — Still on the Road
Numbers are declining — 18 vehicles still getting MOTs in 2025 (24% of peak).
Based on vehicles from this manufacture year that had at least one MOT test in each calendar year. Data from 2016–2025.
MOT History Averages
Most Common MOT Issues — 1983 Yamaha Unknown
Based on actual MOT test records for this model. Percentage shows how often each item appears across all vehicles in this cohort.
-
8.9%
Exhaust noisy
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5.6%
Rear reflector missing
-
5.6%
Steering headbearing has slight free play
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4.2%
Rear Brake indicates slight fluctuation of brake effort
-
3.9%
Exhaust has a minor leak of exhaust gases
-
3.9%
Steering headbearing slightly stiff or notchy
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3.6%
Headlamp aim too high
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3.3%
Rear Wheel bearing has slight play
Data covers a 3-year window centred on 1983. Counts include advisories and failures.
Found a specific Yamaha Unknown?
Enter the reg to see its individual MOT history, AI Hunches, and how it compares to this cohort.