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1950s Matchless G12 650 Valuation Report

Date: August 2025

Historical Overview

Introduced for the 1958 model year, the Matchless G12 (646 cc) was AMC’s larger twin, sharing architecture with the AJS Model 31. The period sport variant, the G12 CSR, added higher-spec equipment and tuning. In the UK, collectors value originality, correct AMC engine/frame pairings and tidy Featherbed-style presentation. Within the 1950s scope, most examples encountered are 1958–1959 (standard or CSR), with prices tracking condition and whether the bike is the rarer CSR.

UK Valuation Summary (by condition and variant)

Condition	G12 Standard (1958–1959)	G12 CSR (1958–1959)	Example External Source (non-link reference)
Project / Restoration Non-runner or incomplete; recommissioning or full rebuild; typical needs include wiring, top-end/gearbox work, brakes and tinware.	£2,200 – £3,200	£2,500 – £3,800	H&H Classics – 1960 G12 garage-find £2,475; H&H NMM sale G12 project ~£2,070
Roadworthy / Presentable Running and usable; largely complete; older paint/chrome acceptable; may have period mods; history helpful.	£3,800 – £5,500	£4,500 – £6,800	Manor Park Classics – 1959 G12 running example £3,795; Bonhams Stafford – 1960 G12 CSR £6,670
Restored / Excellent High-standard restoration or outstanding survivor; matching numbers; correct finishes and equipment; comprehensive documentation.	£6,000 – £8,500	£7,000 – £9,500	Bonhams Stafford – G12 CSR sold £6,670; The Saleroom / multi-house archives

Notes: Verified UK sales include a 1960 G12 CSR at Bonhams Stafford for £6,670 (context for top end of “Roadworthy/CSR”), a 1959 G12 runner at Manor Park Classics for £3,795 (anchors rider band for Standard), and multiple H&H Classics garage-find/project outcomes around £2.1k–£2.5k (projects floor). Sister-model AJS Model 31 results align closely and support these bands.

Value Influencing Factors

• Variant: CSR (sport) typically commands a premium over Standard.
• Originality & correctness: Matching engine/frame, correct AMC cases, proper tinware, instruments and exhausts.
• Mechanical health: Evidence of recent engine/gearbox work and reliable charging/braking lifts results.
• Presentation: Straight mudguards, quality paint/chrome and tidy wiring loom materially help.
• Provenance & documentation: V5C, history file, old MOTs and restoration invoices increase buyer confidence.

Conclusion

For late-1950s UK bikes, a presentable G12 Standard typically achieves £3.8k–£5.5k, while a comparable G12 CSR makes £4.5k–£6.8k. Excellent, documented examples sit around £6k–£8.5k (Standard) and £7k–£9.5k (CSR). Projects run from roughly £2.2k to £3.8k depending on completeness. Originality, CSR specification and overall presentation are the main value drivers.

Source attribution (non-link references): Bonhams – Autumn Stafford 1960 Matchless G12 CSR sold £6,670; Manor Park Classics – 1959 Matchless G12 sold £3,795; H&H Classics – 1960 Matchless G12 garage-find sold £2,475; H&H NMM sale – G12 project c.£2,070; The Saleroom – multi-house archives; Iconic Auctioneers – AJS/Matchless twin results (context).

All Valuations