Sparkplugs. They do more and can tell you more than you might think.

[S750WP]

Hey guys!

 

For my bike, it is recommended that i use a spark plug with a heat rating of 6. The particular recommended spark plug is CR6HSA. For years, i have been using the C7HSA which is 1 level 'colder' than recommended and it is a non-resistor type.

 

I just swapped it for an CR7HSA and it is noticeable much quietier and smoother. Psychological? I don't know. My question here is that, what is actually the best heat rating for a YBR 125? For NGK sparkplugs, i can fit basically 9 spark plugs from NGK. (From my understanding)

 

They are:-

Normal Non-Resistor

C6HSA

C7HSA

C8HSA

 

Normal Resistor

CR6HSA

CR7HSA

CR8HSA

 

Iridium Resistor

CR6HIX

CR7HIX

CR8HIX

 

I understand the benefits of using a resistor type spark plug as it insulates the plug and does not interpreter with the bike's electronics. However, my bike's default recommended spark plug heat rating is 6 (Hottest). However, i have been using 7 (Middle) and everytime i change my sparkplugs, whether DIY or go to shop, it is always recommended that i use one with a heat rating of 7.

 

I understand that too hot a plug will result in, well, a hot engine. Too cold a plug, and the self cleaning process (where the heat is required to completely burn off the fuel, carbon, etc) will not be as successful.

 

The questions here is that, which heat rating should i be using and why do mechanics, spare parts shop uncles all recommend using a spark plug with a heat rating of 7 instead of the manual recommendation of 6? Is it because my YBR engine too hot or is it because a heat rating of 7 is more common throughout Singapore?

 

Thanks.

 

Hi I believe its ok to use spark plug 1 step higher(colder plug) if there is no issue for you to start your bike normally during cold and there is no knocking or abnormal vibraton.

 

Normally the bike manual will specify a heat range of spark plugs and I would choose the mid or the next colder plug, so far been working fine.