Does YZ125 have power valve?
All in all, the compression ratio is considerably lower on the X. (2) Power valve. On the YZ125 motocross engine, the power valve opens at 7500 rpm and is fully open by 9500 rpm, while the YZ125X power valve opens at a much later 8000 rpm and is not fully open until 10,250 rpm.
How much HP does a YZ125 make?
The YZ250F has a slight horsepower advantage. The YZ125 has a 124 cc (7.6 cu in) reed valve-inducted two-stroke engine….Yamaha YZ125.
| Manufacturer | Yamaha |
|---|---|
| Engine | 124 cc (7.6 cu in) reed valve two-stroke single |
| Power | 33.53 hp (25.00 kW) |
| Transmission | 5- or 6-speed sequential manual |
| Suspension | Mono-shock, 13 inches travel |
What is the best year for the YZ125?
A: If you are a diehard two-stroke rider, read no further. The truth is that while we loved the 2005 YZ125 and considered it to be the best 125 two-stroke ever made at the time, it wasn’t going to displace the 2005 Yamaha YZ250F in the minds of American motocrossers.
How does a power valve work?
The power valve is a movable flap located on the cylinder exhaust port of a two-stroke engine – where burnt gasses are flushed out of the cylinder. This helps the engine generate torque at low speeds. As revs build, the flap gradually opens, expanding the size of the exhaust outlet for greater top-end power.
Are YZ 125s reliable?
I’ve owned my share of YZ125’s, and they’ve all been great. The most reliable motocross bikes I’ve owned, and they’re just so much fun to ride. Of course, the newer the better, but even a 1999 YZ125 is a great bike to get started in this awesome sport. There’s also plenty of mods available to make it faster.
Will a 2-stroke run without power valve?
You could run it without a powervalve but it will have no low end.