can anyone tell me how to adjust & set the valve clearance of a 4 stroke 110cc engineand please explain why?

Question

the first mechanic i had tuned up my bike and since then my bike's performance has changed. i have reached 100km/hr before but after the tune up i'm running between 90 to 95 km/hr only and the engine sounds louder than before. the second mechanic tuned up my bike, now i'm running 100 to 105km/hr and engine's noise was reduced. can anyone explain me help me understand how & why?

Answer 1

On any engine you have intake and exhaust valves. For each stroke of the piston (the up and down movements) the corresponding valves open and close. The intake valve opens and a gas and air mixture is put in the cylinder. Then that valve closes, while the piston is headed for the top or in the up movement. A spark ignites the gas and air mixture, and an explosion happens, causing the piston to go downward, since it is the weakest point in the cylinder. Then the exhaust valve opens expelling the used or exploded smoke, and then it closes and the intake valve opens again. Now, if the valves aren't set correctly, then one valve may stay open longer than it should or less than it should. If for example, the intake closes too soon, then all of the gas and air mixture may not get in, or some might escape. The pressure can't build if a valve is open, which would result in less of a "punch" or explosion, when the gas and air are ignited. This would result in less power. If the exhaust valve wasn't set properly, it might stay open too long, causing some of the gas and air mixture that is being placed in the cylinder to escape through the exhaust or it might explode while it leaves the cylinder, which would cause the engine to sound louder.

Answer 2

Always give year, make, engine size and model # when asking questions. We need all of that info to give an informed answer.
Every bike has a different method of adjusting valve clearances.
Purchase a shop manual to get the clearance specs and learn how to adjust yours.
http://www.motocom.com/motorcycles/
Here's one example, but you'll still need the valve clearance specs.
http://www.dansmc.com/index.htm
Go to - Index - Online Repair Course - Valve Adjustment

Answer 3

I suspect the valve clearance was set incorrectly by the first mechanic,too much clearance, hence the noise.Do you not have an owners manual? it should tell you the valve clearances.