With 2 Spark Plugs Per Cylinder, What Happens When Only One is Firing?

 Started the Honda this morning, will run it down to the dealership when it
warms up later in the week so they can do the valve adjustment.

Seemed just a bit rough in the cold even with the choke -- but was great
when it got warmed up a bit.  I do remember from past years that it seemed
to run great with the choke even when cold ... but this morning was VERY
cold.

Just out of curiosity ... what does a motorcycle do if only one of the two
spark plugs in a cylinder is firing?

Since I just replaced the plugs and it was a bit rough (but it was very
cold) this is a natural question.

Any quick way to verify that all 4 plugs are firing?  The obvious method is
to try to run it on 2 then try to run it on the other 2, but there may be a
better way.

--
Jujitsu Lizard (jujitsu.lizard@gmail.com)

 
Two plugs per cylinder is for faster flame propogation.
Running on one plug may cause roughness.

Do not disconnect plugs when testing as this may cause
the charge from the coil to find unwanted paths to ground
with resultant damage.

Easiest choice is to ask the guys at the shop to check it.
Should be little or no cost if they're already doing a
valve adjust.

Second easiest would be to pull and ground the plugs
then check for visible spark as the engine is cranking.

If you've got an inductive timing light, this might also give
you some insight, trying each plug wire in turn and checking
for flashes.

 
What is your opinion on dedicated spark testers, i.e. something like:

http://www.algrovetoolsupply.com/cgi-bin/item/MTN8709

Will that meet the constraints of checking both the coil/wire and the plug,
plus not causing harmful voltages?

Thanks,
The Lizard

 
I'd expect such a tester to work fine, provided you're
careful about contact with hot surfaces. One bozo who
worked on a car we owned forgot to remove a tester
which then melted onto the engine.

You might want an inductive timing light anyway.
Dunno if you've attempted to check timing yet.

 


Or is it smoother and more complete ??  
Flame propagation can be TOO fast.  ;-)