YOSHIMURAtmr-mjn, Racing CDI, Hot wire, Exhaust System on SR 400 are riding in Peiton's Norton type Megaphone.
Speaking of the king of Plug, NGK tends to be more popular than DENSO, but Normal plug ? Comparing NGKWindshield IRIDIUM, DENSOWindshield IRIDIUM, the first engine rotation is Smooth.
When NORMAL is set to full throttle, it is good with NGK, but DENSO is the first engine vibration and Exhaust System sound is Mild, it seems to be close to the ideal combustion matching the engine mechanical characteristics of SR.
Fuel consumption has also increased. (Normal tank Regular full Tan and Eco driving 300 km Over)
Also, the electrode of DENSO is thinner and durability is often discussed, but there is no problem at all.
Imagine that the tip of the electrode was thin and the flame kernel with high energy density was generated, Heart also became hot.
If you want to enjoy Doodo Doko Sound at low speed and low rotation Normal plug, I think that it is DENSO if it attacks the pass with high rotation.
In town riding, docokudo sound is Mild compared to NORMAL and NGK, but in order to become NiceMiddle it should be Mild including character and female treatment.
Even SR laver "NGK it is OK!" I think that there are many NGK believers like, but in such a case please reward one by DENSO.
(Just in case, NGK is also a good plug. To the end please understand individual subjective impression. )