first mods for 400ex? new to four strokes help

[yamasaki_125]

i just bought a 2002 400ex and i was coming from my old blaster that was a 265 with everything imaginable....... i got it dyonoed at 39 horses so i need more power on my new 400


i am thinking about adding a
wiseco 11:1 high comp. piston
hot cams stage one cam
hmf or pro circuit slip on exhaust
k & n filter
and maybe a porting job


i still want it to be reliable but yet have a lot of power and still run on pump gas..... any help or recommendations would be greatly appreciated


also, what are the web sites for JE piston and tc performance?

[RED121572]

Take my mods for example. Its relatively mild compared to alot of ya-hoos on here, but the mods certainly made a huge difference from stock. If I knew then what I know now, I wouldve gone to a 416 kit with a 13:1 compression piston.

www.jepistons.com

Ive ran race gas. Liked it, but a few things lead me back to 94 octane. One of my supplier seemed like he never was at work. The other supplier wasnt open on saturdays. The C-12 that I was using was 5.25 a gallon. On the last rebuild, I found that my cam was covered in lead. The oil wasnt washing it away. And no, my valves are fine. Its normal for a very small amount of exhaust get past the the valves.

I havent experienced any problem with pump gas.

If you want close to 40 hp, I suggest a 13:1 440cc's with a race cam. Ive been told a port and polish is a good mod and Ive been told its not worth the 100's of dollars if your not a serious racer. I have my head polished every rebuild, but not ported.

Theres a jillion others things I could point out, but Ill let someone else have a turn. One more thing though, when I rebuilt mine for the first time, I blew a headgasket shortly thereafter. After doing alot of research, I learned that everytime you rebuild any motor, you suppose to replace all the headbolts. Might wanna take note of that. A blown head gasket cost me another 80 bucks in parts, shop labor...etc

good luck and let us know what you figure out!:D

[DGR Designs]

hot cams 2

[Dave400ex]

I would get an Engine Builders Cam. It would be much better. TC, Sparks, FDO.

[Dune Surfer]

Sell it and buy a C-Dale:p

[yamasaki_125]

could someone please tell me where to buy a duncan exhaust and how much it is

thanx
Eric

[RED121572]

Pick up an issue of Dirtwheels or check out Duncans website.

[Dave400ex]

Duncan Racing (http://www.duncan-racing.com)

[yamasaki_125]

could someone give me the site for marcums? i cant find it anywhere


thanx
Eric

[Derek]

What are you going to be useing your quad for?

[yamasaki_125]

mostly for mx, but do make about 5 trips to the dunes a year.

and could someone tell me how to remove the choke on the carb? what does it do just let it breather better? are there any bad things about doing that?

[Derek]

Forget about the power till you get suspension.

[yamasaki_125]

i have works triple rates with rezzies on their way.... and i wanna get the performance mods before an axle swingarm or a-arms