would the rev box help much when the 400ex only has a white bros full exhaust system and k&n filter and degree key? Would it be worth the money? Also what companys should i get white bros. or big gun? I have herd that after buying the box starting becomes an issue. Is this ture.

 

it won't help for power. i didn't notice anything until i built my motor where the extra rpms are beneficial. i wouldn't get the big gun or white bros if it was me. i have heard good things about the gt thunder and tc boxes. many of the other ones will give you starting issues.

 

It will give you more rpm's, which helps it some. Alba sells one for $59.99. Not bad for a mod that takes 2 minutes to install. Also make sure battery is fully charged.

 

I have a WB Box and I really dont notice the differance. I kept my stock box and i am now using it since it is cold out. The Revbox Does have trouble starting when it is cold (below 40) outside. I have heard of people keeping the stock box mounted and mounting the revbox somewhere close to it so they can warm it up with the stock. I have a WB E series slip on, K&N filter with outerware and it is jetted and i really cant tell the differance with the WB.

 

Save your money. On a mostly stock 400 the power drops off dramatically in the higher revs.

 

Don't buy the White bros rev box, trust me. Consider an Electrix box, which has no rev limiter. I have one and it works perfect. No starting problems.

 

Hey Rkid do you think that degree key makes any difference on the 400ex?

 

dunefool where did you get your electrix box?