An example of an 0.049 cubic inch ( 0.8 cubic cm . ) reed valve engine is shown on the right, taken apart ( with the tools shown ) and assembled.
32.
The engine for all KR-1 models was a two-cylinder, reed valve induction two-stroke motor of 249 cc ( somewhat based on the previous Yamaha TZ / TZR configurations ).
33.
When a negative pulse is induced in the exhaust, air from the atmosphere enters the exhaust manifold through a one-way reed valve and serves to oxidize the carbon monoxide and hydrocarbons in the exhaust.
34.
Unusual for a four-stroke with its typical intake and exhaust valves, the 1981 and 1982 XR-500 utilized a six-petal reed valve set-up between the carburetor and the intake valves.
35.
The Yamahopper is not really a scooter, as the QT50 has no fairing, sports footpegs rather than footboards, and its two-stroke reed valve engine is slung beneath the monotube frame motorcycle-style.
36.
Four-stroke engines are generally associated with a wider power band making for somewhat gentler power delivery, but technology such as reed valves and exhaust power-valve systems has improved ride-ability on two-strokes.
37.
They have all the advantages ( and most of the disadvantages ) of conventional valved pulse jets, but without the reed valves that need frequent replacement-a valveless pulsejet can operate for its entire useful life with practically zero maintenance.
38.
The engine is an air-cooled, parallel twin, six-speed ( in some markets, such as the UK, the first model was sold in five-speed form ), reed valve-equipped intake tract two-stroke engine.
39.
The physical inertia of reed valves means that they are not as entirely precise in action as rotary valves, a rotary valve engine may run better than a reed valve engine at a small rpm range but the reed valve engine often runs better over a wider rpm range.
40.
The physical inertia of reed valves means that they are not as entirely precise in action as rotary valves, a rotary valve engine may run better than a reed valve engine at a small rpm range but the reed valve engine often runs better over a wider rpm range.
