hey i got a 2003 400ex and moddin it this summer. right now i got an e series slip on and a powerfilter for mods. This summer i want to go to a curtis sparks x-6 exhaust,11-1 piston, 416 or 426 bore, stage 1 hot cam, ported and polished, a white brothers rev limiter and an edelbrock quicksilver carb with a jet kit.For better cooling i want to get a bigger oil tank and radiator shrouds. i also am getting an aluminum airbox. as far as the body goes im getting the frame and hubs powdercoated dark blue, gettin silver plastic with a blue flames or tribal K&K graphics kit, AC nerfbars and bumpers, works tripple rate wit rezzys up front on +2inch chrome a arms, works shock wit rezzy on back on +1 inch chrome swing arm, G force adjustable width axle, steel break lines and some other things as well. Does anyone know how much hp my quad will have??And does anyone have anything else i should add to it?? I am also gettin baja rims with razr2s on the back and badlands on the front. will it get more top speed? is it reliable?? what kinds of quads will it beat?? i want to be able to beat stock 450s and rappys. thanks for any input

 

With the motor mods you're listing .. I'd say you'll be in the 40's for HP. If you're hoping to put the spank on some of today's fastest/quickest you might want to look into weight savings too on your beast. Should be impressive when you get it built. It will get more speed by increasing the rev. limiter .. you could also look at getting different sprockets to give you more speed or accelleration. The YFZ is a very quick machine stock .. so accel should be your focus over top speed.

 

Since you're doing so much engine work you should go with a Webcam and hardened rockers. It will give your engine more life than a Stage I Hotcam. A Hotcam is a drop in and works good if you're not doing all those other engine mods. With a 416 or 426 bore definately go for a Stage II or III Webcam.

 

I agree with Red400EXRod, I would go for a top end cam since you are doing the port and polish and getting a Sparks X6. Also, I would not go for the white brothers rev box given that you live in a cold winter climate.. they make your engine a bugger to start in the cold. I'd get a tc racing, gt thunder or a big buck one like the vortex or dynatech.

If you are not overly heavy and can ride well you should be able to take a stock raptor pretty easily and a stock 450R by a little bit with those mods. I'm a touch over 200LBS and with my 416 setup I ran with a piped raptor 690 and beat a stock YFZ and 450R in a 500' drag race. There was a 426EX with a lighter rider on it that was running with the piped/cam moded/intake moded YFZ's and beating the piped/intake moded 450R's. I never asked him what other mods he had, but my buddy asked him what carb he was running and he said it was the stock carb(no nos). [img]i/expressions/face-icon-small-confused.gif[/img]

 

Thanks for the help. I am a light rider only 145 lbs and im hopin to win some races and turn sum heads wit my machine. Any other ideas?

 

I sure do. An 03 400EX with pipe and filter is normally very valuable relative to the money you have invested. Many buyers of used quads are looking for your exact quad and you could get a very good price for it . Now just to make a point, if you spend $3000 on hop ups and handleing you could have nearly bought a new YFZ or 450R for about that amount plus what you get for your 400. The 450s will be much more reliable than the pumped 400 but also they are worth much more.
Unless you have some particular love affair with your old 400 or you want to build a sleeper, it just does not pencil out very well to dump that much into a 400EX. With the newer high performance 450s I'm sure the demand for 400EX hop up mods will be going down. Many buyers of used quads do not want anything to do with heavy duty mods.
It is not the same thing as with a Banshee or 250R where you are building something unique that you will want as a keeper.

 

Your mods sound very familiar to the mods on my quad. I can hang with stock 450r's but not with any mods, I weigh 240, so you should be ok. I do agree with oldturtle, with the mods my quad has I still find myself wishing I had spent it on a 450r. Also I find myself fearing while on slow technical trails that it is going to overheat. It has never happened but I cant get it out of my head.

 

I agree to a certain degree with you oldturtle, but I think the numbers are a bit off.. First off, if you do the work and buy smart you can build a 416/426 or even a 440 engine for MUCH cheaper than $3000. In fact I bet you could build a 416/426 engine for less money than the taxes and dealer fees on a new 450. To give you an idea, I have less than $1000 into all my mods including the nerfs, pipe, hydraulic clutch, cooler, carb, cam, piston/bore, cdi, stabilizer and 450R shocks. I also have about $250 worth of take-off's I could sell to re-coupe some of the money. Yes a 400EX is worth less than a 450.. BUT that's because it's already taken the bulk of it's depreciation. The 450 will not be worth $3000 dollars more than the EX in 2-3 years, I'd guestimate maybe $500 to $1000 MAX. I contemplated the same thing before I started building my 400EX, but after running the numbers I found that building the EX on a budget was the better financial option. Not to mention, I wouldn't find as much joy in winning races on a piped 450 as I do my EX. [img]i/expressions/face-icon-small-wink.gif[/img]

 

i strongly agree with kehn. I am looking into purchasing a 400ex to build as a sleeper since i should be able to get one for cheap.

 

khen sorry