I hate when people ask the same questions

[SoUpX]

I hate doing this to everyone but i cant find anything without getting confused. I have a 04 400ex and I am getting a little bored with the power, I like riding trails mostly and would like to keep my low end power. I know it's still pretty new but it starts right up (even in 30degrees) and havent had a problem except the spark plug got a crack in the ceramic (So i bought a colder plug) I ride it WOT on the rodes when i goto the trails so maybe the extended abuse might have caused this. Other then that i change the oil every 2nd weekend or after it was rode pretty hard with mobil 1 redcap, I dont want to loose my reliability so here is what I propose to do to it.

HMF Bill Balance Full exhaust
Uni Filter
Outerwears lid (similar to EHS, but i dont wanna spend that kind of money)
Stage 1 Hotcam
XR400 head gasket
proper jetting ???? any ideas

eventually i think i want to get a 416 kit but not right now....
I'm not much into drag racing but I would like to beat a piped z400, who usually smokes me pretty bad after 2nd gear..... How do you think this setup will work?


thanks for the replys sorry to sound like a newbie, but i guess i am =]

[TC426EX]

That setup will work great, but I have one suggestion. I really suggest that you add some sort of piston in with that. Pistons and cams complement each other and are almost always done together. boring a cylinder is like 50 bucks and the 416 piston is the same price as a std. bore. I would reccomend doing the 416 while you have your top end apart to do the cam. It really would be the easiest route. In any event, I would add some sort of piston, even if it is a standard bore hi compression deal. Then you will have real noticeable power gains youll appreciate... As for the pipe, and the rest of your components, great choice!

[DaleJrFan]

i know you are worried about power, but dont forget about beefing up the suspension. i am in the same boat as you, still pretty much stock but my engine is still under warranty so the first thing i am going to do is put a set of works tripple rate w/o rezzies on before i get into the engine. also, go with the piston when you do the cam, there is quite a bit of gain with that combo.

[SoUpX]

thanks for the suggestions, I was thinking about this actually but wasnt to sure about the costs, it sounds reasonable enough. I guess that brings up a new question. Will an 11:1 piston make my EX hard to start? And is a 10.8:1 w/ XR400 headgasket noticably different from 11:1? I dont want to replace rings/sleeve every other year. I guess my real question is how do I make a 416 reliable and get max power out of it?

[buster369]

the weisco pistons work great but i don't understand why people go with the stage one. IF u goin to spend money on the cams y not go higher cam even with spending the extra money for the rockers and springs then buying the cam and deciding that you want a bigger one and then have to spend more money buying a more radicle one. As far as gasket wise, just use the 400ex gasket and if you want a higher compression i've herd that you can separate the 3 plated gasket and use one or two by spraying it with high temp paint i believe. there is a tread on the site about that.

[initall]

If you are looking to keep low and mid. I would do.
Big gun slip one great for low and mid.
11.1 high compression piston
stage 1 cam
a rev box to increase the rev limit
Uni filter
proper jetting.

I have this now except for the cam and rev box. which will come next spring. I beat a stock z 400. And he is a better rider than me.

[initall]

the weisco pistons work great but i don't understand why people go with the stage one. IF u goin to spend money on the cams y not go higher cam even with spending the extra money for the rockers and springs then buying the cam and deciding that you want a bigger one and then have to spend more money buying a more radicle one. As far as gasket wise, just use the 400ex gasket and if you want a higher compression i've herd that you can separate the 3 plated gasket and use one or two by spraying it with high temp paint i believe. there is a tread on the site about that.

People go with stage one cams because most of the increase is in low to mid range good for tight trails and hills. Stage 2 cams is for top end. In a bigger bore motor.

You buy a cam for your aplication.

You don't buy the wildest cam for a mildly work engine. You would not benefit without boring and porting.

[SoUpX]

yeah thats the reason i went with the stage 1, because I want to keep some of my low end. From what i understand it doesnt really increase the low end but it keeps it where its at, and boosts the mid-top, where as the stage 2 will lower your low end and increase your mid-top more then the stage 1. I ride alot in the woods, and want that low end to spin thru corners. If i get a 11:1 piston either stock or .080 over (416 right?) then i will use stock head gasket... I was thinking about a CDI but i DO NOT want it to start hard in cold weather, i know it will not start as easy with the high comp piston but i dont want it to be impossible. Is The GT Thunder CDI hard to start with in cool weather with a similar setup? With a 416 and high comp 11:1 comp this should rev pretty quick shouldnt it? I may even need to consider upgrading my oil cooler or at least adding scoops.



If i bore it out, I may do it my self does anyone know the tolerances I need to maintain? How much to bore etc.. All the details, i have access to a CNC mill and lathe, i wouldnt actuallly do this my self but a machinist or engineer could do this w/ no problem for free. As far as the disassembly/ reassembly i feel comfortable with that... This would probably be a good time to adjust my valve clearance too eh....... I may just keep the stock bore tho w/ 11:1 this would be easier........


Thanks for the help