Well I've made one befor and it didnt seem to work but it was prety bad and wasent really long. If you got one that was somewhat long like I've seen on E-bay ya it might work, Try it it might work.
my friend had taken a piece of copper tubing and made it to where the airfilter stuck in between the front shock tower and the bumper and it seemed like id didnt do anything.
If the intake feed for the carb is too long, then it decreases the performance of the carb. The purpose of the cold air intake is to maximize heat exchange in the engine generating more energy and this more power. Cooler air at the intake makes for better performance. Does this mean that an intake pipe six inches long will help? NO.
I've made my own Cold air Intake, works great too, performance was better since I've installed it.
Also I'm soon to Upgrade to what some very few people have done. I will first want to buy a 4-Stroke (Maby), and add a small radiator, fan, and rig it to a small alternator. Hopefully i will achieve this.