How do I know if I'm running too lean or rich?

[bull]

You are running too lean. You can tell from the color of the plug ceramic in the cylinder, or from a gas analyzer, or experience.

I have been piecing together a FrankenScoot 49cc for a scoot repair shop owner. It had many parts were originally sold off including the exhaust, air cleaner box, body panels, etc.

He did not want to spend much money to get it sell able, so i was given a "performance cone air filter". That has become a nightmare to correctly tune. I have been able to get it to run great on sunshiny 80 degree days, but riding in the rain which you could get caught in- it won't get out of its own way!

The reason is the air cools off in rain, thus more compact molecules-- thus more oxygen is pulled in and VIOLA it is running lean.

[coreyman]

Originally Posted by bull

You are running too lean. You can tell from the color of the plug ceramic in the cylinder, or from a gas analyzer, or experience.

I have been piecing together a FrankenScoot 49cc for a scoot repair shop owner. It had many parts were originally sold off including the exhaust, air cleaner box, body panels, etc.

He did not want to spend much money to get it sell able, so i was given a "performance cone air filter". That has become a nightmare to correctly tune. I have been able to get it to run great on sunshiny 80 degree days, but riding in the rain which you could get caught in- it won't get out of its own way!

The reason is the air cools off in rain, thus more compact molecules-- thus more oxygen is pulled in and VIOLA it is running lean.

Is that cone air filter from nibbi? Also how do you know I'm running too lean? How can I tell by the color of the plug ceramic? What color will I be looking for?