2 Spark plugs ?

[gasman]

I know this is going to sound like a silly question but here goes anyway....
Why does each cylinder have 2 spark plugs?
I can understand it they spark at different times but they look to be wired to the came coil, perhaps they are in different positions to advance/retard ignition?
Told you it was a silly question.
All my previous bikes have had only 1 plug per cylinder so I am unsure.
Thanks in advance........

[Jake]

Jan 21, 2011 15:15:22 GMT -5 gasman said:

I know this is going to sound like a silly question but here goes anyway....
Why does each cylinder have 2 spark plugs?

Yep…that’s right.

The NTV/Revere has a three-valve cylinder-head
and uses two spark plugs per cylinder for improved
combustion and (I think) better low and mid-range power….

The Deauville 650 is a similar design and so is the
Honda Shadow Spirit 750. But the most recent Deauville
700 has a four valve cylinder-head and only one plug
per cylinder….

www.topspeed.com/motorcycles/motorcycle-reviews/honda/2006-honda-shadow-spirit-750-ar2726.html

Anyone got a better explanation?

[professore]

It's like those "twin spark" Alfas you see around - right ? 2 spark plugs per cylinder.

[gripper]

Two plugs is for better flame propagation on what is a wide bore and short stroke engine. With a four valve engine there is no room to fit a second plug in, but the plug in that situation tends to be in the centre of the combustion chamber and not stuck on one side.