big bore questions...help!!!

[andy9743]

this is what i have 400ex t-4 slip on alum airbox w/ k&n rejet. i ride trails and fun ride no serious racing. i'd like to up my power some. i don't want to have to run any special race gas. my goal is to be faster then my buddies z-400. what do i need to do? raise compression? aftermarket psiton? 416 kit? i don't know what's all involved in a "big bore" kit and what changes with different compressions so fill me in! what do i need to do to keep my quad ridable like i enjoy to ride and beat that Z!!!!

thanks
andy9743@aol.com
andy

[wvspeedfreak]

Actually your 400ex should be as fast as the z400 with the pipe and filter mods you have(that is if the z400 is stock).Especially in the woods.As far as more power you could install a higher compression piston and a cam in your stock cylinder without having to go to a "big bore".If you stay under 11:1 on compression you should be fine with super unleaded.

[andy9743]

what should i buy? i ride tight woods trails and old fire roads, the z is stock, but brand new. my 400 is an 01, and i think she's getting tired. what compression should i go to? any specific brand? should i do a cam? or will the compression upped and aftermarket piston do enough for me?

thanks

[F-16Guy]

You're going to have it apart anyway, so get an 86mm (406) 10.8:1 JE or 11:1 Wiseco piston, gaskets, a stage 2 HotCams cam, and have the cylinder bored to fit the new piston. That will give you the best bang for the buck and still leave lots of sleeve for future rebuilds if needed. The total should be about $300, including machine work, if you do the disassembly/reassembly yourself. It's pretty easy if you have some mechanical ability, not to mention you always have exriders.com for technical help. :D

[adeptex]

If you spend the $ for a piston and bore, I would go with a 426. It is the same price and will have more power. I went with a 86mm JE(406) piston from stock. It ran good but I was surprised when I rebuilt it with a Ross 440. It has much more power. The compression was almost the same , the only difference was an extra 30ccs. So I am sure that a 426 would have similar results. My $.02

[foleyit]

I think you will be happy if went with a 416 piston of your choice, while you have it open, drop in a Hotcams cam. Decide if you want more bottom end or top. If you want more bottom get a Stage 1, and of course Stage 2 for more top end. Just make sure that your piston compression doesn't exceen 11:1 and should be fine with pump gas.

[nhs333x2]

If you want true power, have the money and you don't want to race get the 465 stroker kit. Nothing I have seen can beat it. That is with a rev box. The kit is made by Trinity motors. Beats z400, raptor, banshee, 400EX ect....