What could I do to a stock 2006 Banshee/ YFZ 450 to get easy power (hp/speed) without spending and cash?

 

With the banshee you could spend $5 and get an advanced timing key which adds a few HP. And the yfz you can take off the exhaust baffle and airbox lid off and rejet and that will add 1-2 hp. Then theres also a cam mod which adds another 1-2hp

 

How would I rejet, and I thought you had to pay money to rejet? What would I do to the cam, and what is the downside of taking off the airbox lid? Also, what I can do to the yfz450 i also could do to the banshee right?

 

you can do ALOT more to a shee than a yfz... but you have to buy two of almost everything