Not just another exhaust ?

[yellowWB400ex]

I just got done "fabricating" a stock 400ex exhaust slip on onto a 250x with a cobra head pipe. The cobra broke and it is a P.O.S. so instead of buying a exhaust I was being recourceful and used what I had. It runs and doesnt backfire. It has descent bottom end but falls off on top (I think) but I have a 400 and the 250 is my friends and dont ride it much. So my questions are is this bad? Will it be ok? And what should the jetting be around, I have no idea where to start?

[LazeR]

I dont see why it would be a bad thing. As far as jetting i couldnt tell you since i dont own a 250x, but i would just do a plug check. Make sure there isnt any exhaust leaks or anything, and i would say you're set! I doubt you are getting any extra power or anything from it though

[muddy400EX]

u should cut eveything out of the stock 400 muffler, put a core in it from an aftermarket pipe, then put packing around it. and then, cut it really short. i dont even know if this is possible, but it would be cool:blah:

[yellowWB400ex]

It is possible and I was thinking about it.

[yellowWB400ex]

no one has ever tried this even on a 250x or 300ex

[kilabeez0]

nope. offtopic how do u like your R4? $350 on ebay is a good deal i'm thinking about it.:macho

[yellowWB400ex]

the R4 is nice it puts out more power than th HMF because my friend just bought one (slip on). I beat him off the line and through out. It isnt a really cracky sounding pipe but a deeper mellower. It is louder than the HMF:devil:

[kilabeez0]

but u realize your friend only has a slip on while u have a full exhaust

[04'400ex'er]

Originally posted by kilabeez0
but u realize your friend only has a slip on while u have a full exhaust Yea, I have never really herd of the R4 being a heavyweight for the 400, and have never herd of one outrunning a HMF. But you never know.

[cals400ex]

those WB's pipes with the promeg headers produce pretty good power actually.