Non resistor spark plug

[Howe]

Hi everyone,
I'm curious and hope you can fill in. If my moped using injector thus using spark plug cap with resistor, can I use non resistor spark plug? Will there be any negative effect in the long run?

 

[barryh]

Shouldn't be an issue if you are using a resistor plug cap as they are usually a minimum of 5K ohms. Depending on the type of ignition system, using both a resistor cap and resistor plug is not a good idea as it will weaken the spark. In fact it will always weaken the spark regardless of the type of ignition system, it's just you won't notice with electronic ignition but you might with points ignition.

Didn't understand the relevance of "injector"

 

[Howe]

Shouldn't be an issue if you are using a resistor plug cap as they are usually a minimum of 5K ohms. Depending on the type of ignition system, using both a resistor cap and resistor plug is not a good idea as it will weaken the spark. In fact it will always weaken the spark regardless of the type of ignition system, it's just you won't notice with electronic ignition but you might with points ignition.

Didn't understand the relevance of "injector"

many people says if modern engine which using injector and thus an ECU will damaged due to non resistance spark plug produce much bigger voltage compared to resistance type spark plug

 

[Ride_Red]

Why not just use the correct plug that is recommended in the owner's manual? I've found that is usually the best choice.

 

[BigCahuna]

If you were to use a resistor plug, I would remove the resistor in the cap. You only need to have so much resistance in the circuit. It's usually around 5k, on a new spark plug if you were to check the resistance with a multi meter. I'm surprised they still make non- resistor plugs. Back in the days of point ignitions, that's when they were the only choice. How old is your moped?.,,

 

[Howe]

Why not just use the correct plug that is recommended in the owner's manual? I've found that is usually the best choice.

I want to try old brand of spark plug, AutoLite which only produce non resistor one for carburetor type engine. a friend of mine says that non resistor spark plug provide better ignition compare to resistor spark plug

 

[Howe]

If you were to use a resistor plug, I would remove the resistor in the cap. You only need to have so much resistance in the circuit. It's usually around 5k, on a new spark plug if you were to check the resistance with a multi meter. I'm surprised they still make non- resistor plugs. Back in the days of point ignitions, that's when they were the only choice. How old is your moped?.,,

my moped produce around 2021, Yamaha with 115 cc inline engine. it comes with NGK CR7HSA spark plug and a resistor cap