With currency fluctuations and inflation adjustments, the 2020 Yamaha YZ250 costs $7499, while the 2020 YZ250X costs $7599. Q: HOW DOES THE YZ250X ENGINE DIFFER FROM THE MOTOCROSS-TUNED YZ250?
The TM two-stroke motor was redesigned last year with electric start. TM has TPI as an option.
The YZ250X has a 1-inch-lower seat height when compared to the YZ250 (38.2 inches versus 39.1 inches). Given that the YZ250X uses the same frame, wheels, suspension components, shock linkage and plastic, we don't know where the inch came from.
On the trail, the YZ250X has a classic two-stroke feel that makes plenty of midrange to top-end power but has a noticeably smoother transition from the bottom-end to the midrange in comparison to the motocross version. It could use a little more low-end torque, but it's nothing a quick stab of the clutch can't fix.
2020 Yamaha YZ250F Dyno TestWe ran the YZ250F on our rear-wheel dyno to determine peak output from Yamaha's 250 four-stroke motocross bike. We documented 38.2 hp at 12,500 rpm and 18.5 pound-feet of torque at 8,500 rpm.
YZ- Yamaha zinger. RM- Race model. WR- wide ratio. SX- supercross. Not sure about KX or XR.
Because combustion takes place with each revolution of the crankshaft with a 2-stroke, this format puts out more power than a 4-stroke engine and the power has more instantaneous delivery. This are some reasons why 2-stroke engines have a long history of use on many different types of motorcycles.
For weekend warriors and beginners, a newer 250-cc 2-stroke offers the ridability of most 4-strokes, minus some torque. Plus, they're less expensive to maintain. A 250-cc 4-stroke is also a great option since it's less expensive, lighter and easier to ride for a beginner.
At peak, the KTM produces 37.50 horsepower, while the YZ125 makes 34.84. That is a 2.66-horsepower difference in favor of the KTM.
In the dirt bike world the F designation has come to (usually) mean the bike is a four stroke instead of a two stroke, such as a CRF250R vs a CR250R or a 250SX-F vs a 250SX.
The history of the KTM 250 SX dates back to 2002 when it was released as one of the fastest two-strokes in the market. KTM has equipped the bike with multiple upgrades since then to make it more powerful and reliable on the track.
Will this hurt anything? All production motocross engines are designed to run on the 91-octane American unleaded premium that can be purchased down the street (however, if you live in Europe, American 91-octane gas is equal to European 97-octane gas).
2001 was the last year of the CR500 then Honda discontinued them. This was due to the AMA 500 motocross races which were discontinued back in 1993. Instead, Honda spent most of the funding on the cr250 over the years. Now days, there is a new series of CR500 dirt bikes that come from Service Honda.
It is the fastest stock dirtbike that I know of. Some say they do around 100 mph.
the CR500 two-stroke pumps out approximately 55 horsepower, to the 50 horsepower of the CRF450. If you doubt those numbers, you will be convinced by turning the throttle wide open on both bikes. The CR500 explodes, while the CRF450 churns its way forward.
Claimed horsepower was 67.59 HP (50.4 KW) @ 8500 RPM.
| Honda CR500 |
|---|
| Fuel System | carburetor. keihin 38mm flat slide |
| Ignition | capacitor discharge (cdi) |
| Spark Plug | NGK BR8EG '84-91 , '92-01 |
| Transmission | Gear box: 5-speed Final Drive: chain Clutch: wet plate |
Honda is planning to bring back two-strokes with a clean-burning, fuel-injected, all-new screamer engine. Patents have just been published that show the side and front elevation of a new two-stroke engine from the big H.
Honda stopped manufacturing the CR 85, 125, 250cc 2-Stroke dirt bikes in 2008 and the CR 500cc 2-Stroke dirt bike in 2001. Now, I do understand that one of the reasons they have stopped making these 2-Stoke bikes is because that these bikes burn oil.
12 Fastest Dirt Bikes in the World
- Husqvarna FE (163 km/h – 101 mph) – 510cc.
- MuZ Baghira (164 km/h – 102 mph) – 660cc.
- Honda XR (177 km/h – 110 mph) – 650cc.
- Husqvarna TX (180 km/h – 112 mph) – 300cc.
- Aprilia RXV 5.5 (182 km/h – 113 mph) – 549cc.
- Suzuki DR-Z (183 km/h – 114 mph) – 400cc.
- KTM 450 SX-F (198 km/h – 123 mph) – 449cc.
