set your HSN, and LSN to flush, then you only need to adjust the large gold needle to get started tuning...you may need to lean out the LSN slightly.
turning it right will lean it out (less fuel, run hotter)
turning it left will richen it up (more fuel, run cooler)
i would suggest leaving the truck alone for a while before you cause possible damage with blind tuning.
do some quick research and get a better understanding of how tuning work's, there is alot of good info, and alot of picture's to help you understand.
you can also download the factory HPI manual for your savage from hpiracing.com, in that manual it will show you how to setup your savage, to factory setting's, and tune from there.
i recommend the following tool's, part's for tuning:
fresh fuel that you plan to use all of the time
extra glow plug's (O.S. #8 is a good medium/hot plug)
small flathead screwdriver
8mm glow plug wrench/socket
temp gun
do your research, and try your best to get all of the above in order to tune, and keep a tune on your 4.1 savage.
tune's change day by day for the most part, as weather changes or parts get add'd you will need to re-tune..its an important part of nitro engine's.