I copied this from another site this is what is wrong with your SV to start.
SV650 headlight upgrade
The headlights on a stock SV650 are yellow and dim. They won't grab the attention of anyone on the road.
Unfortunately you can't just slap in a brighter bulb. The reason is that the bike (like 99% of bikes on the road) contains no relays. There is a 1-2 watt power drop because the power to your bulbs go through small wiring in your handlebars to the switches. A relay will bypass and give you a solid electrical connection without much power loss.
Thus upgrading your headlights is a two step process:
- Install relays
- Install brighter bulbs (optional)
Relay
You can make your own relay kit, or you can buy a premade one.
Eastern Beaver makes a H4 kit that is plug and play. Visit the link and scroll down till you find "H4 Dual Headlight Relay Kit". At the time that I am writing this article, it runs $54.95.Once you install the relay, you should expect your stock bulbs to increase power output by a noticeable amount.
A 40-70% increase in light is typical.