Originally Posted by Dredd
I only lean it out 1hour on days colder than the ititial day I tuned it. Or on a day hotter than the day I initially tuned I would richen it up 1hour.
A common tuning mis-conception by a lot of people.
On hotter days you need to lean your engine because there is less oxygen molecules per cubic ft. of air. Many people think you need to richen the engine on hotter days to cool it more.... if you do, it will run like crap. You just have to balance your comfort level with temperatures as to how far you lean it on a hotter day. Maybe you'd also run a #8 on a hotter day or shim the head 0.1mm. If you richen a .21 on a hotter day I almost guarantee you hit second gear way late or not at all because the engine is way too fat and not making enough power to engage the two speed.
Colder days are just the opposite.... more oxygen molecules per cubic ft. of air, hence you'd need to richen the engine and possibly run a #6 plug (if you were running a #7).
You give the engine what it wants when the weather changes and kinda just live with the temperatures
