When changing your twin to complete stage 1,TDs, AC and PCIII, do you need to go to a hotter spark plug to burn the extra fuel or will stock do? Whats everyone running and how is it working? Still 40 thousandths gap?

 

I didn't. Still running the original plugs.

 

I use HD GOLD!

 

I changed to NGK Iridian (SP?) plugs. They are pricey but my bike seems to run better and get much better fuel mileage.

 

Recommend ... stay with stock or if you must upgrade, gold, but that's it.

You don't want or need a hotter plug.

 

I use Autolite 4164 plugs with a .040 gap.

R&R Cycles installed them when they did my dyno tuning, and I've left them in ever since. They use them in every motor they make, from the normal mild street buil all the way up to the 155" (190torque/185hp) street/strip motor that they make.

And they are like a buck a piece............can't beat that.


Steve

 

Ihave found that other than original interferes with a race tuner and causes the system to throw an engine light code.

 

For a stage I mod the standard heat range plug should be adequate. As we increase the HP per cubic inch of an engine enough a colder plug is often required. As the combustion chamber heat increases we need a colder plug that vents the plug's tip heat better to the engine's cylhead to prevent the tip from getting too hot that could cause pre-ignition.

 

Thanks to all who replied, I guess the SE plugs would be to much. I will stick to the OE HD plugs.

 

I have the stage 1 and the PC lll, tried several other plugs and the bike did not perform well at all. Went back to the stock R12 HD plug with stock gap. The idle and midrange performance improved. Also, now the check engine light does not stay on when I start the bike. I even changed out my plug wires and coils and bike did not preform well on other than stock plugs over time.

Unless you are racing I would stick with the stock HD plugs, they are cheap and get the job done not effecting the engine managment system. I change mine every 5,000 miles.