Got some new plugs for the bike with 29k on it. In looking at the Service manual they have the setting to be 0.038-0.043in. Question is why the range an not just a setting? What are most of you gaping your plugs?


Thanks

 

Was told it would run better at 0.038, don't know why.that's where I run mine

 

Depending on your tune. Stock probably runs better with the smaller gap. If you run richer than stock it will likely run better with the wider gap. I run mine at 45 with the PV and it runs great.

 

If it is a platinum or iridium plugs it will ruin them when you try to gap them. Most plugs are pregapped so you might want to just compare them to each other to make sure one has not been dropped & lost the gap.

Toby

 

Back to basics. Ohms law:

The resistance of most objects is constant and only varies with temperature. Electric companies increase the voltage to increase the current. Since R is constant and R=V/A, increasing V means A will also have to increase to keep the R constant. If electricity were water flowing through a pipe, the voltage would be the water pressure. The current would be the amount of water the pipe could deliver in a certain amount of time. The resistance would be anything which worked to prevent water flowing through the pipe.

In other words, if Voltage is a constant, the lower resistance is, the higher the current (Amperage) is.

Fine wire electrode spark plugs have a lower resistance. So do most high end plug wires. This increases current.

Now take into consideration, there are a few other things that increase resistance. Static compression ratio, and cam timing come into play. Greater cylinder pressure = greater resistance.

Bottom line is, there is a reason most high end race teams (NASCAR CUP, N.H.R.A. Pro Stock) are NOT using a off the shelf spark plug.

Do a Goggle search and take a look at the $50.00 a piece and up plugs these teams are using.

THERE IS SOMETHING TO IT!

 

.005" won't make an appreciable difference to your ignition system. If you're a perfectionist, shoot for .038" and let erosion open the gap through the range as it ages.

 

Set it at .040

 

.043 and 3 tenths

 

oh dear.

plugs should always be checked before install ( don't forget anti-seize paste on the threads)

gap should be as wide as possible with-out misfire- if misfire occurs, reduce the gap.

the gap spec for a stock plug with stock wires is calculated to allow for the fastest, most complete burn of the mixture- which allows for more time advance, better emissions, power and economy


extra-awesome special plugs and wires MAY NOT complement all stock ignition systems and MAY degrade performance.

Mike

 

I gap them at the middle of the given range. [like 040 in this case] You"ll never get them exact anyway-if ten people gapped a set of plugs at 040,you'd actually get 10 different gaps anyway.