It is a popping resonating sound generated by a lean condition on deceleration. When you suddenly close the throttle, the incoming air is choked off and the closed throttle also causes the bike to return to idle on the very lean idle circuit.
The reactivity series of metals was deduced by performing several experiments in the lab which enabled scientists to arrange metals according to their reactivity with dilute acid, oxygen (air), and water.xides of iron and copper are insoluble. Metals that are less reactive than copper like silver, gold and platinum do not react with oxygen. Note: When aluminum reacts with oxygen, a layer of aluminum oxide adheres and covers the aluminum.
Copper is one of the most important metals. Copper is reddish with a bright metallic lustre. It is malleable, ductile, and a good conductor of heat and electricity (second only to silver in electrical conductivity).Its alloys, brass and bronze, are very important.Monel and gun metals also contain copper.opper metal is not particularly reactive and indeed is found as the free metal (native) on occasion. Copper sulfate is [Cu(SO 4)(OH 2) 4 ].H 2 O in the crystalline state; it is particularly well known and was often called blue vitriol.