Engine Cutaway
An interactive cutaway of the 197 cc air-cooled Lifan 200 (163FML) single — the same unit that fills the Lifan class in NZ grass-kart racing. Watch the piston, connecting rod, crankshaft, push-rods and valves move through the four strokes, or grab the crank and turn it yourself.
Valve lift
One lobe, so these are the same curve shifted by 207.5°.
Crank angle, degrees. The line marks where the engine is now.
Cylinder pressure
Last completed cycle, with the valve events marked.
Peak 5 bar. Crank angle, degrees.
Pressure against volume
The area inside the big loop is the work. Log scale, so the pumping loop shows.
Cylinder volume, cc.
Torque and power
Two plots, one rpm axis — a shared axis would invent a crossing point that is not in the data.
Sweeping the dyno, 0%
Show the numbers as a table
| Crank° | Inlet lift, mm | Exhaust lift, mm | Cylinder, bar |
|---|---|---|---|
| 0 | 0.59 | 0.69 | — |
| 45 | 3.55 | 0.00 | — |
| 90 | 6.31 | 0.00 | — |
| 135 | 5.75 | 0.00 | — |
| 180 | 2.32 | 0.00 | — |
| 225 | 0.12 | 0.00 | — |
| 270 | 0.00 | 0.00 | — |
| 315 | 0.00 | 0.00 | — |
| 360 | 0.00 | 0.00 | — |
| 405 | 0.00 | 0.00 | — |
| 450 | 0.00 | 0.00 | — |
| 495 | 0.00 | 0.07 | — |
| 540 | 0.00 | 2.14 | — |
| 585 | 0.00 | 5.62 | — |
| 630 | 0.00 | 6.37 | — |
| 675 | 0.00 | 3.78 | — |
| 720 | 0.59 | 0.69 | — |
Running
Cycle
Controls
Space start/stop · ←→ step the crank when stopped
Close the throttle and manifold pressure collapses, residuals climb and the burn goes ragged — the engine idles on the bleed past the slide, exactly as it does on the kart. Wind the brake load up to hold it at low revs and the crank visibly drags through compression and snaps forward on the power stroke.
Specification
Why this model says less than the badge
15 N·m from 197 cc works out at 9.6 bar BMEP, which a 9:1 air-cooled pushrod single on a 26 mm carburettor does not make. Lifan's own net figures point the same way as this model does.
One cam lobe works both valves through two followers, so inlet and exhaust necessarily share the same lift and duration and differ only in phase. The drawn lobe is the same function that lifts the valves.
The torque peak sits near 4500 rpm where the real engine peaks around 6500. There is no wave solver here, so no exhaust scavenging and no intake resonance — the size of the curve is sound, its peak sits low, and that is recorded rather than tuned away.