Motorcycle Repair: Yamaha1100 transmission? noise, air induction system, ais system

Question
2003 v twin new to me. Hear random sharp banging, rattling almost like pinging but louder (Premium fuel always used) when shifting up. Seems to come from front of engine (inside transmission?) when accelerating. Do you think this a timing chain or possibly engine valve noise? I understand the Yamahas are quite noisy. Thanks

Answer
Jim,

-without being able to hear it my best guess
is the AIS system noise.

-A.I.S. (Air Induction System). This is an emissions
control system that allows air to be drawn into
the exhaust downstream of the cylinder head to
ignite unburnt fuel vapor.
This may cause some popping or backfiring.
It is the gadget on the left side of the engine
with some hoses attached.

http://www.nopork.com/tech_ais.asp
http://www.star-riders.org/starcruiser/volume4-1/ais_1100.html
http://www.vstar1100.com/