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Old 17th April 2006, 02:28   #1
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Default 2 valves per cylinders

hello folks,
i was just wondering why damn motorcycle manufacturer manufacturing only 2 valves per cylinder engine in india? why not more than two valves . if i am not wrong then only kinectic GF series,LML energy,adreno bikes comes with more than 2 valves per cylinder. more valves means more responsiveness as well as smoothness in engine . my LML NV-spl express 5 has 5 valves and is a hell smooth and can compete with 100-125CC motocycle? any suggestion boyz. why in india more than two valves per cylinders are not coming .......WHY.............WHY........WHY??? and one question difference between OHC vs SOHC vs DOHC engines , i know their full form but i want technical differences? right
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Old 17th April 2006, 04:50   #2
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Devsus,

Well its part of evolution i guess, and as you know most manufacturers in the indian market are still selling outdated stuff.
2 valves also means less parts, simpler engine and therefore cheaper. But things are starting to change.

OHC - OverHead Cam-shaft. Which means that the camshafts directly push open the valves (or via rocker arms) and the cam is connected via a timing chain (im guessing its chain driven for bikes as well), or if its not OHC, then the cams are gear driven in the block with pushrods actuating the rocker arms which in turn push open the valves. Less efficient.

Ok, that was a confusing explaination. This might make it a little more understandable.

For the question of which is better, look at TBHP: Which Engine Is Better? DOHC vs SOHC (Which engine is better? SOHC vs DOHC)

cya
R

ps - OHC is also Old Honda City on this forum

Last edited by Rehaan : 17th April 2006 at 04:52.
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Old 17th April 2006, 08:11   #3
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Quote:
Originally Posted by devsus
why not more than two valves . if i am not wrong then only kinectic GF series,LML energy,adreno bikes comes with more than 2 valves per cylinder.
I feel your pain. I would love to see a high revving RFVC Honda 250.
I think only the GF 170 is 4 valve head. LML is probably 3 valve.

Quote:
Originally Posted by devsus
more valves means more responsiveness as well as smoothness in engine . my LML NV-spl express 5 has 5 valves and is a hell smooth and can compete with 100-125CC motocycle?
More valves mean more airflow and more horsepower. Vespa NV is 2-stroke and has no valves......but it has 5-port head.
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Old 17th April 2006, 10:28   #4
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thanks........guys u guessed right? thank u very much
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Old 17th April 2006, 16:59   #5
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hi ,be it 4 valves or 2 valves ,the size of the valve makes a lot of difference . Imagine 2 half inch size pipes would be the same as one 1 inch pipe . The area occupied by the valve is more important . sometimes ,manufacturers fool the general consumer by stating that the engine has more valves . the best example would be the matiz ,it had something called as "goliath" valve ,meaning bigger valve .


just my 2 cents
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