I would like a new modification for my 400ex.
How much would a big bore kit cost? 440? 416? I don't know. What am I going to have to pay when it is all over? How much of a difference in Hp and torque does one make? I don't have the option of changing my gasoctane very much. Only to about 98-100.

would a pipe be a better first modification? What is the best? White E brothers? Supertrapp? Yoshimira? I ride around my house in a quarry, in some woods, on roads. I don't want it to extremely much louder, don't want it annoying.

thanks for the help

 

not sure about the overall price on a big bore kit bu i love my white brothers pipe. its alot louder than stock but if its to loud for ya, white brothers also makes a quiet core insert for around 30bucks.

 

Get new tires first!!!!!! All the pipes you listed are much louder then stock.

Get a 14t front sprocket. Unless you ride at
70mph all the time you should notice a huge improvement in power!

I think I remember a post a while back about you selling your 400ex. What happened?

 

considering I will be riding in snow in about 2 weeks... I doubt that sur traks would be such a bad tire! I am very happy with them so far.

 

440 kit is roughly $285 for piston and sleeve and then you pay for labor and/or boring. The 416 kit is roughly $130 since you need only the piston and then labor/boring. Boring runs $30-50. I say the best modification would be Works front shocks.

 

400exs suck!

 

As far as pipes go, the Duncan Double Barrel was hands down the best pipe I've tried on the 400. For big bore kits, I run a 425 and I'm very happy with it. I've rode a few 440's and I don't think that the power is quite as smooth. Some people prefer the extra torque but I'd trade a few ponies for the smoothness/throttle response. Any which way you choose, watch how high you take the compression on your motor. 11.5:1 is probably as high as I'd go as I've been seeing lots of 400's with higher compression pulling the studs loose and wiping out the threads in the jug.

Travis
GNCC / District 11 Harescrambles
1999 400EX
1998 RM125

 

VERY impressive bigdogx. VERY VERY impressive. How did you come up with that??
Exer

 

Hak...do you mean that boring costs $30-$50 for the first or second oversize? Going up to the 416cc kit normally costs $100+ around here. Just trying to help initial poster in determining total price!