Not a expert on this engine, but learned a LOT from this site about it.
On my 06, When first got it, it would backfire big on shutdown.
a Little on Decel.
Found the two screws, (Header into Cyl) were loose.
Took them out, 'anti seized', them, then snugged them up.
Checked where the header clamps to the muffler,
that was also loose.
Also, opened the idle screw, a bit, (By Sound)
Idle at 800, screw out, 1/8 turn at a time, and 2-4 min listening,
idle went up, then when it went down, backed off, tell it was highest again.
Then set the Idle, (warm engine, at about 1050)
(And I always use, 'Non-Oxy' gas)
Backfire went away. When I start hearing little, 'puffts' at shutdown,
just go back to tightening those screws again.
Now, if I 'want', (and sometimes I do). It is high revs, clutch in, and as I park, hit the 'kill' switch.
Quote:
... By changing the idle-mix mixture, will this also help save the valves from the notorious lean mixture that comes directly from the manufacturer? ...
If gained, only, ONE, piece of advice/knowledge from this site.
It is Well worth it ! It was the:
"This is a OLD Engine".
Even though it may be a 2015 model year.
It still is a OLD,
designed engine. And it needs Zinc (ZDDP) in the oil. Something that is NOT in most oils today.
Knew that for my other 'old' ICE's. And used additives.
But, 'RED LINE', was Compatible with wet clutch.
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1344471565Using, Rotella oil, and Redline. Will allow that engine to run Many, Many, Many miles. And, you will not, 'need', another.
(Higher amounts, perhaps first 1000 miles, then slowly lower each oil change)
Now, Just to be clear;
The words: 'need' and 'want',
Mean, Two Different Things!