Yamaha XT500

1976–1981

The big-bore four-stroke thumper that started the whole Dakar legend — winner of the first two Paris-Dakar Rallies and the bike that proved a simple air-cooled single could out-last anything in a desert.

Overview

Engine: 499cc air-cooled SOHC single, 2 valves, 87 x 84mm bore/stroke, 9.0:1 compression, single carburettor, kickstart only (no electric start)
Power: 30PS (22.0kW) @ 5800rpm
Torque: 38.2Nm @ 5400rpm
Transmission: 5-speed, chain final drive
Frame: Half-duplex steel cradle, doubles as the engine oil tank
Suspension (front): Telescopic forks
Suspension (rear): Twin shocks, swingarm
Brakes (front): Single-leading-shoe drum
Brakes (rear): Single-leading-shoe drum
Tyres (front): 3.00-21
Tyres (rear): 4.00-18
Weight (dry): 139kg
Weight (wet): Unknown
Seat height: 830mm
Fuel capacity: 8.8 litres
Top speed: 100mph

Price guide

good: £5,000.00–£7,000.00
rough: £2,500.00–£4,000.00
excellent: £8,000.00–£12,000.00

Known issues

Oil-in-frame weld cracking (Dealbreaker)
The XT500's frame backbone is also its engine oil tank, so any weeping or seepage around the headstock is a serious red flag — it usually means the front end has been twisted (a heavy off-road impact or crash) hard enough to crack the welds joining the oil tank to the frame. Check closely around the headstock and down-tubes with the bike cold and dry; a crack here is a frame-replacement job, not a quick weld repair on a 45+ year old structure. TODO(verify): get a second source pinning down whether this is a widespread pattern-failure or mostly crash-damage driven — forum discussion (XT500/TT500 Forum) treats it as an inspection point rather than confirming a specific design-defect rate.
Piston and bore wear (Info)
A big, hard-worked single will rattle on a worn bore/piston even when otherwise sound — listen for knock under load, not just at idle. The bottom end itself (roller bearings throughout) is comparatively tough and rarely the source of the noise.
Weak 6V electrics and points ignition (Check)
Original 6V electrics and points ignition were undersized even when new, and 45+ years on, tired coils/points/regulator combine for a weak spark and reluctant hot starts. Confirm the bike starts cleanly hot as well as cold, and check whether a 12V/electronic ignition conversion has already been fitted — a common and well-supported upgrade, see below.
Wet sumping (Check)
A worn check valve lets oil drain from the tank (frame) into the crankcase when the bike sits unused, so the engine smokes heavily on the next cold start until the scavenge pump clears it. Ask when the bike was last started and watch the first start closely — a cheap check-valve rebuild kit cures it, but persistent heavy smoke after a fresh rebuild points at the Eaton-type oil pump itself.
Tank, seat and bodywork are year-specific (Info)
Fuel tanks and seats changed across the 1976–1981 run and don't all interchange. If bodywork looks non-standard, confirm the parts actually match the bike's model year before assuming a straight swap is possible.

Upgrades

Electronic ignition + 12V stator conversion (moderate)
Replaces the original points ignition and 6V system, which gives a weak spark and reluctant hot starts, with electronic ignition and a 12V stator for easier starting and genuinely usable lighting.
- XT500 Electronic Ignition Stator Kit & 12V Up-Grade — Rex's Speed Shop
Oil check valve repair kit (easy)
Cures wet sumping — smoke on start-up and a dropping oil level — by replacing the worn check valve seal, ball and spring that let oil drain into the crankcase when the bike sits.
- Oil Valve Repair Kit | XT500 | SR500 | TT500 | XT550 | 583-13113-00 — Rex's Speed Shop
Regulator/rectifier replacement (easy)
Replaces a tired original 6V regulator, a common weak point that leads to inconsistent charging and dim or blown bulbs.
- XT500 Regulator 1977-1985 6V — Yambits

History

The bike that invented the Dakar

Launched at the 1975 Paris Salon and in showrooms from 1976, the XT500 was Yamaha's first big-bore four-stroke single, and the first Japanese off-road bike built around one. It was a deliberately simple recipe — one 499cc air-cooled cylinder, five gears, kickstart only, no electric-start complexity to go wrong a thousand miles from a dealer — and it turned out to be exactly the right recipe for the event that didn't exist yet when the bike was designed.

When Thierry Sabine's Paris-Dakar Rally ran for the first time in 1978/79, Cyril Neveu won it on an XT500. He won again in 1980. The XT500 beat the BMW R80G/S to that particular piece of history by a year, and in doing so more or less invented the idea that a big four-stroke thumper was the tool for crossing a desert — a template every adventure bike since has borrowed from.

The oil-in-frame trick

The XT500's frame isn't just a frame — the backbone tube doubles as the engine's oil tank, a neat weight-saving trick common on big British and Japanese singles of the era. It works well when everything's sound, but it means the frame and the oil system are the same component: a welding repair after a crash, or corrosion inside the tube, is an oil-system problem as much as a structural one. See Known issues for what that means when you're looking at a specific bike.

What it's like to own

Beyond the issues below, the XT500 is about as mechanically honest as classic bikes get: one cylinder, one carb, a five-speed 'box, and roller bearings through the bottom end that shrug off decades of use. The reward is a bike that's genuinely simple to work on yourself, with an active, knowledgeable owners' community and a decent aftermarket still supporting it. The trade-off is everything you'd expect from 1970s Japanese electrics and a kickstart-only big single — starting technique matters, and the fixes below are the ones almost every owner ends up doing sooner or later.

Sources

If anything on this page is believed incorrect, please let us know and we will update it accordingly.