Why 2 cams?

I was discussing about mechanic with my buddy few days ago and we were asking ourselves:" Why 2 cams?"

We understand easily why the overhead cam, we understand why 4 valves or even 5 instead of 2 but why is it more efficient to put them under the control of different cams ???

Thank you

It eliminates the need for rocker arms. It also keeps the valve angle straighter that it would be with one cam and a shim and bucket system. The key is it is simpiler. ---Mike

Cool!! :)

Thanks again! :D

direct cam to valve contact allows them to rev so high, and to still be reliable... less to break, less to adjust, less weight to spin around...


It does allow more RPM but who needs that many R's on a dirtbike. DOHC is also much heavier than a SOHC. It also is much harder to adjust the valves although you don't have to quite as much.


In addition to the reasons listed above there is also advantages with being able to make split lift/duration and timing between intake and exhaust that is not as easily done with a single cam.

Math, for all this good information we Americans are giving you please PM some profanity to use while I'm driving in Quebec.

I'll be up there next Fall and I don't want to go unarmed. :)

Thanks to all of you for these explanations...

Hey Beez, Don't want you Americans to come here to blast us!!! :D :D

But man, are you crazy :D, why do you want to come in Québec in fall :D....You'd better buy yourself a good winter coat!! :D :D


I can handle it buddy, I've hunted in SK in December. :)

That is part of the RPM thing. I want the easier to maintain and lighter SOHC setup. I think somewhere down the road someone will come up with a good pushrod setup. Lower CG , Less head heat.


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