Yesterday while I was running my Savage 25 the clutch bell heated up to the point of melting the spur gear (due to the fact that it was hot and I was trailing riding and going through ditches). Took apart the clutch and the shoes looked fine. I worked on the whole assembly to where it would spin more freely with less friction. I then replaced the burnt up 47tooth spur gear with a 49tooth spur gear. I adjusted the gear mesh where it's not too tight or too loose. Everything was put back together good. When I went to run the truck today the engine was running 40 to 50 degrees too hot. Like it was running too lean. Could my new clutch adjustments and spur gear cause it to be running too lean. I haven't tried re-tuning it cause I'm afraid of it over heating. Any help would be highly appreciated

The baronetric pressure might have changed. Along with the ambient temp. Don't be afraid to richen it slightly to compensate for these changes. That will knock the temps back as the fuel actually helps cool the motor. As well as a lean motor fires hotter. That's why when a racer uses a nitrous system, it's crucial they not lean the motor out. Otherwise when the nitrous hits, it will knock holes in their pistons. Seen that first hand on a stroker 400 smallblock.

So just fatten (richen) it up some. Good catch on the temps rising on the motor.

A higher spur gear can make the engine rev higher. That's probably it.

Barometric and ambient temp change influences on nitro are overrated, unless you live somewhere with a radically changing climate...

Just richen the HSN.