i had 50/100 watts in my old vn an had no problem untill i change the highbeam to 100watts as well then i started to blow fuses but for just the h4 i never had a problem
You need to know what the stardards use. If you are putting in a bulb thats going to suck the power you will blow fuses and put pressure on relays (maybe). Could be illegal too if they are too bright.
I was told by a auto electrician that using anything above standard will help to fade the reflectors faster because of the heat generated by the brighter lights.