I have broken the weld between the pipe and the muffler twice, Has anyone experienced this? also the steel bracket broke also. They have already repaired it once.

 

no, but I am thinking about buying one. would you recommend? Did you have to pay to get it repaired?

and..... one more question, how much does your rev kit improve power?

 

Neither I or 3 of my friends have experienced this. I don't know how you ride, but we ride on wooded trails mostly. Not real big jumps, but we do get some air, and we do ride aggresively. I don't know why your breaking it.

On the rev box, you won't gain anything at all! A stock 400ex stops making power at 7,000 rpms. The box is set at 9,000. the only way you'll gain anything from it is, if you go to a big bore kit and a new carb. The black box isn't doing anything for you....

 

Neither I or 3 of my friends have experienced this. I don't know how you ride, but we ride on wooded trails mostly. Not real big jumps, but we do get some air, and we do ride aggresively. I don't know why your breaking it.

On the rev box, you won't gain anything at all! A stock 400ex stops making power at 7,000 rpms. The box is set at 9,000. the only way you'll gain anything from it is, if you go to a big bore kit and a new carb. The black box isn't doing anything for you....

 

The rev kit will let you stay in the powerband a bit higher, but people over rate these.
If a motor is tuned to produce power at a certain RPM and then dramatically decline in power, why go try to rev it out higher?
The cam of the 400ex is tuned to top horsepower a little over 7000rpms. Only way your going to make more horsepower with the rev kit is by using a different grind cam. Many high performance cams are grinds that yeild more power on the top of the powercurve and thus will benefit from letting the motor rev higher because the motor is still making power or not dramatically losing power at these high RPMs.
Basically don't waste your money on the rev kit unless you like to spend money or if your motor is tuned to produce power at a higher rpms than stock.

 

White bros. gave me authorization to return it. They said they had some with bad metal. This is the second time in the same place. I know that it beats the big gun system and saves about 250.00. I am pleased that a company stands behind their product so well. Also, as far as the rev kit I would highly recommend it for climbing(hillshooting). I run against my friend with the same set-up and I was taking him on the hill until he got his.They only work (in my opinion) on the lower gears. I never really rev out 3,4,5 gear. If you don't hillshoot you probably never would use it because of the need for the torque at high rpm's.