Deacon, I've run all kinds of 2 strokes starting with Grand Dad's ol' Scott Atwater outboard which used 30 weight non detergent at 16:1 originally.
Talk about smoke on the water....it was like we were foggin for misquitos.
But one thing remains consistant, use a good grade of oil BIA/TCW, observe the suggested mix ration (perhaps richer with oil for break in), and read your spark plug often.
I'm probably telling you stuff you already know but some of the others may be less experienced.
On plugs it may be worth while to make certain you have the exact plug for your engine that the manufacturer suggest. Then visit the parts supply house and see if you can run down where that plug is in the heat range. Is it a hot, medium, or colder plug running plug. If you want to switch to another brand it may be worth pulling the cylinder head and fitting the plug to observe if the reach of the plug stops flush with the combustion chamber with only the electrode extending past the surface. If a plug reach is too short.....you loose compression, and if it extends too far into the combustion chamber the threads absorb heat like the cylinder cooling fins and make the plug run way too hot. Often people grab those plugs on a display card at WalMart or Lowes and slam em into the engine and it runs so they use it. Fortunately in a string trimmer or blower it's only for a few minutes each week but on a motorized bike it can lead to troubles. 2 cycle plugs can run 15% to 30% hotter than 4 cycle plugs and running hottest at lower speeds.
I always run resistor plugs, especially in points and condensor ignition systems. The resistance cuts the destructive last electrical cycle (spike) and
enshures the slower eroding of the point surface. It also doesn't make the
neighbors radios etc buzz when I ride by. (something to remember when riding by a police cruiser and your ignition tears up their 2 way radio)
My grand ma's ol weiner dog always seem to know when I was coming minutes before I arrived. She though the dog was psychic. It wasn't until one day my dad was riding the bike to get some gas for the lawnmower that I realized what the dog knew. At about 2 miles away there was four way stop and the Grandmother always had her kitchen radio playing. When dad pulled out from that stop the radio made a revving buzz and the dog shot to the door barking to get out. I had originally thought it may have been the exhaust note of the bike but had a big truck been in front of me or the wind blowing in a different direction she wouldn't have been able to consistantly know I was coming. The radio on the other hand was the dog's early alert system. After I installed the resistor plug the dog would only go barking at the door when she head me coming up the street. I don't know if dogs can think like we do but I'm sure they can reason.
On reading your plug, you need to have a few new plugs and your tool kit and ride out to a long stretch of highway where you can ride several minutes in a straight line at your top speed. Have a magnifying glass and flashlight in your kit too. Install a new plug, fire it up and go like you would usually ride.
When you're ready to stop, kill the engine with a kill switch abruptly and coast to a stop. When the engine has cooled after a few minutes pull the plug and read it. If the ground electrode or center electrode look like they are rounding off then you may be overheating......from lean mixture or improper timing. I was taught that if the ground electrode appeared to be effacing it could be mixture, but if the center electrode held in ceramic insulation is porus and grainy looing you may have a timing issue. It should look clean and fairly white.
If your center electrode appears to have small metal balls cling it it and some black specks then your mixture is too lean. It may even coat the center electrode with an aluminum colored coating. (aluminum from the piston)
If you look deep into the open end of the plug.......where the ceramic meets the metal shell of the plug that is where the electrode runs it's coolest. There may be a ring of carbon around that part of the ceramic in there. Yet the tip be fairly white and clean. This should be the look of a 2 stroke engine that is getting a good fuel air ratio thru the carb. If the fuel is mixed with oil at 40:1 and that deleivered into the engine at 15:1 (fifteen air to one fuel)
thru the carb then the engine should be running well. The carbon colored ring
will be present but possibly faint. Outboard 2 strokes may run 50:1 to 100:1
ratios. They may run CDI ingitions and variable spark duration systems to extend the dwell and spark duration.
Some 2 strokers are now using exhaust gas temperature with a sensor to
switch between ignition timing profiles.
But learning to read plugs is an art everyone here should take up.
Seventh up from the bottom of this page is a link to reading plugs with color photos and explanations:
http://www.bcchapel.org/pages/0003/kolb.htm
