1978 Yamaha OW31 Ex-Works Formula 750 (Johnny Cecotto Collection)

Customer TZ750s filled Formula 750 grids. The OW31 did not. Yamaha’s own archive calls it a factory machine for World F750 and Daytona — the works OW29 engine in a compact chassis derived from the YZR500, with magnesium and titanium pieces the production bikes largely lacked, and power eventually claimed around 160 PS. It was built in very small numbers solely for contracted riders. Steve Baker took the 1977 title on one; in 1978 Johnny Cecotto and Kenny Roberts fought the series on them. The customer TZ750D was developed from the works bike, not the other way around. That is Path C without special pleading: works iron that was never a dealer catalog item.

Cecotto’s 1978 Formula 750 World Championship is public Yamaha history — three wins that season and a five-point margin over Roberts, per factory season notes and the Bonhams catalog race log (Italian, French, and Belgian rounds among the wins; seconds in the UK, Austria, and Spain). This lot is catalogued as one of the two identical works OW31s run for him in that championship year and again, unchanged, in 1979. Diligence matters on identity: when Yamaha ended the F750 program, the team’s numbered chassis went back to Japan under the customs carnets. This machine had travelled to Europe as spares on an unnumbered factory spare frame. Yamaha presented it to Cecotto with a quantity of parts; he assembled it himself. Motociclismo’s 2000 technical comparison — scanned copy on the Bonhams file — still concludes it is the genuine championship-winning works machine. Rare Machines reports that conclusion and the spare-frame fact together; we do not collapse them into a cleaner story than the paper supports.

What is documented on this frame is not thin. Cecotto confirms he rode it at Imola on 7 October 1979, captaining the Rest of the World team at the AGV Coppa delle Nazioni and winning all four races he started against grids that included Roberts, Mamola, Pons, and Lucchinelli — period press travelling with the lot. On 13 April 1980 he won the Imola 200 on it again, ahead of Lucchinelli and Roberts — his third Imola 200 victory after 1975 and 1978. The bike then sat in his ownership for two decades. Pettinari recommissioned it once for Motociclismo’s wet Monza demonstration in October 2000, then drained and laid it up. It has never been restored. Works power-jet carburettors remain; Roberts’ American-run OW31s used different carbs — another period fingerprint buyers can ask about at inspection.

Score 93 — Ultra-rare. Production points sit just under the RC173 sole-survivor ceiling because multiple OW31s existed and this example’s numbered sister chassis returned to Japan; specification is full works F750, not a TZ customer bike; provenance is a World Championship works fleet machine with continuous famous custody and major Imola results on the present frame; documentation is strong (catalog, Motociclismo exam, period press); market appearances of unrestored works OW31s are exceptional; condition points credit originality and long dormancy without pretending it is race-ready. New marque and a non-Honda motorcycle for the Live board — clean diversification beside the Hailwood RC173.

Status: Live catalog — Bonhams Autumn Stafford Sale, Lot 237, 11 October 2026. Live-cap note: rotate Jordan-Ford 191/3 (90) — lowest Ultra on the board; this machine is clearly rarer and diversifies.

Watcher’s checklist

1. Read the spare-frame / numbered-chassis-returned-to-Japan note in the Bonhams catalog before you equate this with a stamped 1978 race chassis still in Japan.
2. Confirm engine 409-200173 and power-jet carburettors against the Motociclismo file and inspection.
3. Separate 1978 F750 championship program claims from the 1979 Coppa / 1980 Imola 200 results documented on this frame.
4. Plan UK import / NOVA / buyer’s premium — estimate is not hammer.
5. Budget a full recommission after long storage; Pettinari’s 2000 lay-up is not a 2026 start certificate.
6. Re-check Bonhams Lot 237 status before you act.