Topic: Slight misfire on the number two cylinder.

[Magilla]

Bike: 76 CB750K

Problem: 

Starts on first kick and idles fine.  When riding at lower RPMs it pops a little out of the number two cylinder. It is as if it is not quite firing at 100% in that cylinder alone.  If I bring the RMPs up it seems to get better.  I say seems because it's hard to tell for sure.

Any thoughts on this one?

[mono]

my car is doing the exact same thing on the #3....

 did you check the plugs (gap/corrosion) and wires?

[Magilla]

I'm going to pull the plugs today and regap them.

[bender01]

Could be the plug caps. Maybe it needs to be trimmed to get a new connection. Try running it on idle in the dark and see if the spark is lighting up around the plug.

[Duke McDukiedook]

If the problem persists after checking spark then go to a dry then wet compression test to see what numbers you get.

[lucky]

You can clip on a DC inductive timing light to any of the cylinders, and the light will not have a constant rate of flashing if that cylinder is not firing.

[Magilla]

You can clip on a DC inductive timing light to any of the cylinders, and the light will not have a constant rate of flashing if that cylinder is not firing.

Lucky,  talk me through this.  I have a timing light.

[lucky]

You can clip on a DC inductive timing light to any of the cylinders, and the light will not have a constant rate of flashing if that cylinder is not firing.

Lucky,  talk me through this.  I have a timing light.

Is it a clamp on inductive timing light where you just put on the outside of the wire? (See photo below)

Just clamp the pick up on a spark plug wire when it is running and shine the light on a dark surface. sometimes in bright daylight you can just look into the timing light. Is the light flashing consistantly.

Now test each cylinder. If one of the plugs is not firing all the time, you will see it.

[Magilla]

I will run the timing light test. That will be a fun new thing to try.  I've had th light for years and now I have a use for it. I pulled the plugs today and regapped them. It seems to be better but not perfect.