Mods

[yellowWB400ex]

I am really thinking about getting a 11:1 piston and a stage 2 hotcam. Could I run a higher comp with all the gaskets and will the rod hold up, I really dont want to go over 11:1 too much. How much should this cost me? And will I notice a big difference with these mods? What will the difference be?

[400exrider707]

I currently jsut rebuilt my quad with 11:1 wiseco (std bore) and a hotcam stage 1. When you run all of the 400ex gaskets your not getting even close to 11:1. The rod should be fine with that compression. I see you already have a full exhaust so this mods should compliment it well. You can get a wiseco piston kit on ebay for about $100 shipped but if you want like a JE you're probably lookin at $125. Ross is also another option. It's hard to say how much better my quad is since there is snow everywhere. It definitely runs smoother and has quite a bark to it now. Revs a lot quicker though. I think you'll be impressed. The compression piston will give you good bottom and the cam will give you mid and top, so you should be all set with those mods.

[bpimpdaddy21]

Right before the wintertime I installed the same piston an cam (11:1 Wiseco, Stage 2 HotCam) in my 400EX. This should cost you no more the $250 for piston, gaskets, and cam. It ran me about that from magicracing.com. I will let you know, that with my mods listed, there was a much noticed difference over what it was before these mods. The quad seems to pull harder down low, all the way up to the top. When you do these mods together they seem to compliment each other, and work out great. I may also suggest a new CDI box at time of these installs. I installed the GTThunder Rev box in my 400EX also at the same time, so I recommend that, raised rev limiter, advanced timing, I am VERY happy with all of these mods done, come highly suggested by me also.

I might add that it was a simple install also, took me and the bro about 3-3.5 hours total. If you are mechanically inclined at all, do it!

[markk]

I was told that i should buy my suspension first, But i didn't i bought my motor work!
Im gona tell u the same thing that i was told, I would keep that money outa your motor and at least buy front shocks for your 400. That will help u go faster than a motor could think about.
If i could do it all over again from when i bought my bone stock 400 in Aug03 i would do it in this order.

Tires, bar setup, Suspension,stearing stablizer,gas tank,motor work, aftermarket a-arms/swinger,Roll Footpegs, rims. That might not be everyone thing, But from what i have learned with my first year racing, is i did make mistakes with the products i bought, But i will know for next time.

But my motor has done me well, I would stay away from the 440 big bores, And if u go with the 425cc kit (89mm) piston make sure u get a aftermarket oil tank to keep it cooler!

[bpimpdaddy21]

Let me also add that if you decide to go the suspension route, get the shocks and a-arms and swinger at the same time, or just get the fronts with arms or the back with a swinger separately, but get the whole front or rear suspension at once, this way you wont have to get your shocks redone when you get longer a-arms or a longer swinger!

[397ccEX]

11:1 is set for std bore and all you need is new gaskets right?
Is their a need to rejet im interested in dooin the same thang

[yellowWB400ex]

Im not going the suspension route because of the $$$. I really dont want to do it my self because I dont trust myself. So I figure it should cost about $400-$500 for the piston, cam, and gaskets when its all said and done(when I bring it some where else). Does this sound right???