Sounds like the compression release solenoid might not be functioning correctly. I'd start by checking the cables the solenoid pulls on to see of they are slack and need adjustment. Also look at the wires going to your solenoid to see if they're loose or shorted. Most likely it just needs a cable adjustment.

Here's a YouTube video detailing what I'm referencing. It shows a VL1500, but I'm pretty sure the C90 has a compression release solenoid too.

 

Decomp Valve Adjustment

 

It could be a problem with the starter not releasing when current is applied by thumbing the starter switch. The starter could be sticking and not opening up once the button is pressed.

 

Hello all I have a on going problem with my vl1500 c90 boulevard 2008 it seems every time I turn around I’m have a issue with my bike clicking and sometimes starts until eventually it leaves me stranded I have put 4 new stators on this bike and I have did the wiring up grade and all along my decomp solinoid has not been hooked up and my bike as it wasn’t hooked up when I bought this bike and at 1st it ran fine for a while off and on with this starting problem; up until now and all I did was install 3” big shots and removed my pairing valve with a g man block out kit then crank the bike took it for a ride and came back home put it up only to find the next morning all I hear is the decomp solinoid clicking and the starter won’t enguage, new starter by the way, and also when I try to cross over the starter solinoid the starter will engage but will not completely turn the motor over as if it’s kicking back so I pulled the spark plugs and that don’t work either it’s the same thing, this dam bike has me so upset I can’t think straight has anyone ever had this problem because I can’t find that anyone has on the internet, any help would be appreciated thank you. (I also hooked the decomp back up and I have it adjusted correctly)