I'm using a white brothers R4 slip on with a 155 main right now i tore it apart and noticed the spark plug tells me it's lean. I have the needle in my hand. I want to make it richer but how much? I hope I'm heading in the right direction. Also I ride with the lid off and a high flow filter. Thanks to anyone in advance.

 

Are you using a Dyno Jet kit? Just follow the instructions from there and jet accordingly.

 

no dyno jet kit. I changed the pipe and jet about 5 months ago. Seems to be lean now that it's warmer out.

 

Things usuaullay run rich if it's warm out. And if it's humid it will run even richer.
later
Superstar

 

plugs are hard to read on a four stroke, not like a two stroke.
Im running a full CT pipe with a 160 main jet, I had a dynojet needle and it was to rich, I went back to the stock needle and it runs better.
Before you checked the plug was it idleing, 1/2 throttle, or full throttle?

 

sence you are too lean you need to ajust your main jet larger