As of round 17 Race · updated 10/13/2026, 07:18 PM (Japan time)

Riders

Jan Kostwinder

No freely licensed photo found, so the race number and team colour are shown instead. About photos

Nationality: Netherlands
Bike: Yamaha

Birth date and place from the official rider profile

Career

Made a Grand Prix debut in 125cc at Daytona in 1964.

In 125cc (1964–1965): 2 starts, 0 wins, 0 podiums. In 350cc (1969): 1 starts, 0 wins, 0 podiums. In 125cc (1973): 1 starts, 0 wins, 1 podiums.

First podium: Isle of Man 1973 (125cc).

In all, 4 Grand Prix starts, 0 wins and 1 podiums (within the official results database).

Written automatically from the official results database (no opinions about the rider)

Note: these totals are incomplete. The official data has no result for 1 races in seasons and classes this rider raced in; they are not counted: 1965 125cc (TT)

Season by season

125cc350cc ★ Champion

The strip shows each year's team (team colour). Tap for team and machine

Scope: official results DB, 1964–1973 (the rider's racing years); excludes 1 races with no official result data

Totals

125cc1964–1973

Win rate0.0%

Podium rate33.3%

Average finish (when classified)avg P7.0

12 pts · Poles 0

350cc1969–1969

Win rate0.0%

Podium rate0.0%

Average finish (when classified)avg P9.0

2 pts · Poles 0

Points are counted per class, never added across classes. Tap a number for the list of races | Scope: official results DB, 1964–1973 (the rider's racing years); excludes 1 races with no official result data

Against the greats, and the class of their debut

Grand Prix debut in 1964. Of the 49 riders who debuted that year, 0 also raced in 2026.

Greats: 2+ world titles or 30+ MotoGP / 500cc wins. Up to 4 who shared 10+ races, most titles first. A finisher counts as ahead of a non-finisher.

Results by condition (races)

All classes 4 races · 125cc / 350cc

By circuit (best average first)Small sample

Isle of Man125cc 1avg P2.0

Daytona125cc 1avg P9.0

Assen125cc 1 · 350cc 1avg P9.5

Average finish across classes (Moto3, Moto2, MotoGP and so on together). See each class below for class-only figures. Only circuits with 3+ races count as a best track.

125cc 3 races · 1964–1973

By circuit (best average first)Small sample

Isle of Man1 racesavg P2.0

Daytona1 racesavg P9.0

Assen1 racesavg P10.0

125cc: all in the Multiple suppliers era; no track-condition records; no grid records.

350cc 1 races · 1969

By tyre eraSmall sample

Win rate

Podium rate

Average finish (when classified)

350cc: no track-condition records; no grid records; one circuit only.

Fewer than 30 races: small sample (dashed). Average finish counts classified finishes only | Scope: official results DB, 1964–1973 (the rider's racing years); excludes 1 races with no official result data

Distance ridden and distance travelled

Counted from 1949 (lap lengths before 1998 researched from published sources: estimates)1 races with an estimated lap length

Ridden on the bike

Every session

at least 113 miles
0.0× around the Earth · 3 laps

From 1949. Every session in the seasons with the lap analysis documents, races only before. Tests not included. Laps × that year's lap length.A minimum, calculated from straight-line distances between circuits. Connections, tests and trips home are not included, so the real figures are longer.

Every race

No season as a regular (starting at least half of the races)

? How the estimate is made

Estimate = average of the last 3 races before each absence

Seasons in which at least half of the races were started | Scope: official results DB, 1964–1973 (the rider's racing years); excludes 1 races with no official result data