Everything you said sounds good, but there is no reason to check the timing. With the electronic ignition the timing is controlled by a position detector on the crankshaft, and the ECU moves the timing around based on throttle position and (I think) engine rpm. There is no way to adjust the timing, its not like setting points, so there is no way someone could have set the timing wrong.
If the throttle position sensor has failed then the timing wont be advancing correctly, the bike would be sluggish as hell and maybe idle crazy fast. If you are not seeing any indication of those things then check the compression and put the vacuum gauges on and see if the carbs are out of balance.
You are on the right track.
Another thing you can do, just like with any gas engine, if the jets they put in are too big the bike will be running very rich. The exhaust will have that distinct 'old car' carbon smell, and your plugs will turn black on less than one tank of gas. Checking the condition of your plugs is a good indication of the jets being too big or too small. The caviot is you have to have clean (new) plugs in there to begin with then see if the jets are fouling them black or maybe burning them white (jets too small - wrong jets for the bike).
You will pull the plugs out for the compression test, so its a freebee
Dont know if anyone has mentioned this: I tell everyone: if you dont have a torque wrench go get one from harbor freight. Even a cheap one is better than none. A 3/8" drive is all you need.
Nearly everything on a motorcycle that you put a wrench on puts a steel bolt into an aluminum part. There is no 'feel' for tightening bolts into aluminum. It feels snug..snug..snug.. then it strips out. This is the single most important thing to know for a motorcycle, even with simple things like spark plugs (12 ft lbs).
Also if you dont have it already the Yamaha Vstar 650 factory service manual is free online in PDF format. All the torque specs are in there.
Last edited by KCW; 11-02-2018 at 01:39 PM.