Ok I brought a bike can't really figure out if its a regular 600 or the f4i cause it has the f4i kit on it. It has a tail light kit on it I see everyone talking about a tail light converter I don't see that on the bike but the blinkers work also brake lights just won't get brighter can someone please help me

 

Look at the vin on the frame to find out what exactly it started life as. If you can post
a picture, from the side profile, we can probably tell what changes have been made, if any.

As far as the brake light, itself, have you checked the bulb? It, likely has 2 elements
in it. The brake element may be burnt/broken. Always check the easy things first. ;-)

Hope this helps, Ern