how much more power does a fmf pipe give a 400ex?

 

I have an FMF Powercore 4 (squared).I really like it.I have had to drop a tooth on frt sprocket for bottom end but sure does improve top spped if that is what your looking for.I also like it because it is one of the few performance pipes that has a spark arrestor-I ride blm/forest ground sometimes.

 

According to the March 2001 issue of Dirtwheels the FMF Power Core with a K+N 155mj and arrestor puts out 26.7 max. hp, which is slightly less than stock.

 

i also have the power-core iv-2. it made a huge difference. i was happy with it stock but when i added the pipe it was like a whole new machine. i just put the powerbomb headpipe on a few weeks ago and it made a similar difference in power. i clobber my friends stock 400's and all the modded one's except the 440.

 

Dont get my pipe, worst pipe ever, not impressed at all, but i just have the slipon, dont know about the full exhaust, my friend has a yoshi and it is so much faster.