Spark Plug Gap

[demeter]

I just replaced my spark plug and noticed the one in there was gapped to barely 0.30.

The mfg spec says 0.60 to 0.70. I gapped the new one to 0.65 and she sounds and runs great.

Do you think there was a reason the person who owned it before me gapped it so small?

Kymco Like 50cc

[tclhb]

My factory plug was gapped much tighter than spec on my Like. I noticed it running better after too, but I also adjusted the exhaust valve and replaced the air filter. That's one negative to doing several things all at the same time. I don't know which made it run better.

[de dee]

 I have a iridium plug in my downtown, do they come pre gaped,  I never seen the garage check when they installed them  in my van,(  toyotas you have to take 1/2 of top off of the motor to get to the plugs in the back,)

[demeter]

I have a iridium plug in my downtown, do they come pre gaped,  I never seen the garage check when they installed them  in my van,(  toyotas you have to take 1/2 of top off of the motor to get to the plugs in the back,)

Yes, they come pre-gapped but maybe not at the right gap for your vehicle/scooter.

My new plug is an iridium and it was gapped at 0.80. I had to make it smaller.

[TLRam1]

Make sure you are reading and using the right measurement scale.

[Vivo]

If the engine has a forced induction system or has Nitrous applications the gap needs to be lowered. Since your ignition coil makes the same voltage if combustion pressures are increased without increasing voltage the gap becomes harder for the spark to jump across hence the need for a smaller gap. Never trust a plug manufacturer to have gapped the plugs prior to packaging, always check the gap and adjust accordingly.