spark plug

[TM426]

IS there a better spark plug to run with a 426 kit and wich one you recommend?

[cals400ex]

try the NGK dpr9z. this is one step colder than stock. when the bike is cold, it may be tougher to start. it is recommended by ross and je. i run it without any problems.

[TM426]

It really starts fine when its cold, dont you want to run a hotter plug for better burn (sorry if I send ignorant)

[EX4me]

The 9z should help your engine run cooler instead of running the 8z which will cause it to run hotter. Heat=loss of power.

[TM426]

Cool THANKS!!!!

[cals400ex]

yeah, the 9z is supposed to dissipate heat a little better. it has been known to keep the head a few degrees cooler, but not a ton of difference.

[04'400ex'er]

As far as the colder plug, any plug that has a higher number than 8(9) will be cooler. I run a DPR9EA. Personally, I couldn't tell any difference. And you want the coolest motor possible, It will last better and run harder.Every little bit counts I guess.:rolleyes: