I use to have a 250R three wheeler that I putholes in the air box but abviosly to many becaause it leaned out and scorched the cylinder walls. (wont do that again) But thats different it was 2 stroke yours is 4 stroke.

 

you should have re-jetted lol

 

Tell me about it lol

 

Holes in the air box make a big difference as long as you jet for them and have a pipe, without a pipe i'm sure they would make a noticable difference with a high flowing air filter. Oh and the stock main jet for the 300ex is a 122, you have to go richer if you want to open up the airbox. well that was the stock jet in my 98.

 

I thinck i was 13 when i drilled the holes in the air box Im 16 now andI know better LOL

 

haha, whats wrong with taking the air box lid off? and if its bad, how many holes, were and how big?

 

on my 250r i covered the lid with 1 inch holes. I should have just took the lid off. I would have had the same results (blown moter LOL) but with the same results

 

Cruiser, you can take the lid off, but if you ride in alot mud its not a good idea

 

cutting holes will make a noticeable differance.What i did is cut the part were the snorkel is off.you also will need to run a larger jet.For the air-filter i would run the twin air or a K&N with an outware.