I'm after a diagram of the Boulevard C90 original

open headlight.. theres a plug in there that's for the spare circuit (take lens off front of headlight- 2 screws one either side

The oil filter is behind the metal plate next to the exhaust pipe on the right side of the engine.It is held in with three hex head bolts.

how do you remove the swing arm from susuki c90

I have a c90 boulevard (2005) , my gears jump time how do I reset them?

As long as the lightbar's power is less than 50 Watts and you secure it with it's own seperate fuse (5Amps for 50 Watts) I believe you don't have electrical issues. Use seperate lines directly from the battery and use a switch to turn it on only when your engine is running. Of course you may have warranty issues with your dealer if you install it.

Hook Voltage meter to battery while bike is running should show around 14volts around 1000RPM if not something bad in charging system

My Clymer manual has good diagrams.
The 30 amp fuse that protects the charging system on my '07 C90T is located behind the left upper cover. Yours is the same.
You have to remove the steering head cover and the chrome speedometer section to get to it.
Yep. blow the fuse on a trip and you better have tools so you can get to it.