QUOTE (Backcountry @ Sep 11 2008, 05:20 AM)
index.php?act=findpost&pid=10539They are widely used by the moddy mountain snowmobilers out West. Ive used them on my ATVs over they years but they arent as handy as they are with a sled- where elevation changes and sweeping temperature differences can tweak your tune.
The biggest mistake people make with them is to not establish a baseline from reading plugs and piston wash. You absolutely must establish a baseline reading 1st. Then you can set about tweaking and fine tuning in your set-up from there. If you just use a general rule that 1250*F is max EGT, you could very well melt a piston like Bobby says above happens to him at 1180*F. You may find your motor will melt a piston at 1050*F, or that it runs its best at 1350*F. Each motor varies and probe placement will also vary and influence what that max EGT allowable will be. They are a nice tuning aid when used correctly.
I have a digitron on my cub. And as everyone says you need to establish a baseline and once you do. tuning is a breeze.....