Jetting/Timing/Plug heat range

[Dirt Bike Dan]

I just had the flywheel and stator off my '83 250, and I was having starting troubles. I got that sorted, but know I'm curious. I plan on jetting the bike this summer, because I know its wrong. The bike almost always smokes (black/gray/white), and plenty of exhaust splooge. I was wondering how the jetting, plug heat range, and the timing (stator adjustment) all relate to each other and the bike's performance. How can I tell when the bike is too lean/rich? I remember reading somewhere turning the stator plate can result in more power/harder starts or easier starts/less power, depending which direction I rotate the stator. After searching and reading a lot, I still don't understand the benefit of a hotter/colder plug. Anyone know?
thanks for any replies

 

[Tom L]

An easy way to tell if you're too rich is if the spark plug is wet and black or the spooge. You should just stay with the recommended plug heat and adjust your jetting. I don't believe there is any advantage to going hotter or colder. That's usually a last resort, I believe.

 

[Green Hornet]

If your riding tends to be slower, technical a hotter plug will help. If your riding is fast to WOT go with the standard plug. The manual recommends a hotter plug if you experience fouling. I run a hotter on my 05 220. If I know my riding is going to be WOT alday I will goto the BR8ES but otherwise I use a BR7ES

 

[Dirt Bike Dan]

thanks. What about too lean, that's my main concern. If it's a fresh plug, it would probably be white, but are there any specific sounds or something else to indicate it's lean?

 

[Green Hornet]

When I had a lean condition, it sounded like I was running out of gas or you could get a bog when opening the throttle rapidly. Eric gorr has Plug Pic on his website. Take a look