Engine vibration, 3700-4K, very slight, anything to worry about???

[81gs7501166]

It's always had this very slight vibration, from bout 3700 to 4000 rpm. Only noticeable during light throttle. It's not changed in 3000 miles? It happens in all gears, more noticed in 4th and 5th. Did they all do this, or maybe my 1166 pistons or G3 cams have caused this. All my other bikes have some sort of vibes at some rpm. Just wondering if 1100s had any known problems?
Also anyone ever experimented with advancing the cams for more bottom? I don't need all that top end drag race power any more?
And what about the charging system mod I keep seeing it pop up? Is it necessary?
mine has always operated fine.
If I understand correctly, this is kinda a bullet proof engine, in mild tune?
that's the only reason I put the 1166 jug and pistons, and g3 cams in, leftover race parts from a guy who upgraded for more power(I gave 200$ for machined and prepped jug, slightly ran pistons, and cams that hardley had any shine).
I'm old enough now that bullet proof is more important than ET.

 

[fbody_mike]

I will say my Bandit 1200 engine buzzes the most at 4500 rpm. I notice it mostly in the mirrors. More so, if I am at light throttle and the carbs need balancing. After I rebalance the carbs, it drops a lot.

 

[Steve]

Check valve clearances and carb sync (in that order), vibes will likely be reduced.

.

 

[81gs7501166]

Ok, sounds reasonable, I'll put valve adjust and carb sync on my to do list.
neither have been done in a while.
Sync with drill bit? 1st, or only use gauges?
do I use stock specs on G3 cams?
Thanks.
Ps-its really smooth before3700, and after4k.