400 to stomp 450

[chevy400racer]

i was wanting to know if there was a way to bore out a 400 with other performance parts ( like top of the line stuff) that would beat a average 450R rider.... but with the 400ex being fairly reliable and not a maintance machine???? give me some answers
along what kind of performance parts?

[exrider49]

what kind of race are you talking about?? if its mx or xc i would say suspension first then practice, practice, practice, and if you wanted motor work just do a bore like a 426 or even a 440 and get a cam, high comp. piston, get your head ported and polished, do bigger valves and see if you could get titanium ones, and get sum hard faced rockers and im sure there is more but thats what i pulled off the top of my head

[chevy400racer]

uh i was just wantin like a drag race down like a straight road.. but i am planning on doing cross country racing...

[400exrider707]

Simple answer: No. Sure you can build one to beat a 450R, but will it be a reliable machine with low maintanence? No way.

yeah your not gonna beat the 450's in reliability and maintanance if your going to bore your cylinder and get a bunch of other stuff done. In XC you can beat them because it depends on more skill and how quickly you can conrtol the machine at speeds but for MX your not going to be beating a 450 on the straights i can tell you that right now

[chevy400racer]

well what kind of stuff are you talkin reliability wise.... im not going to do ant half a** stuff here.... im talkin 2500-3500 dollars in motor and carburation work here? i was thinkin a 426

[JOEX]

Originally posted by chevy400racer
well what kind of stuff are you talkin reliability wise.... im not going to do ant half a** stuff here.... im talkin 2500-3500 dollars in motor and carburation work here? i was thinkin a 426
That much for a 426?

Couldn't you get a well built (quality) stroker motor for that kind of money?

[yfzrider45]

with 2500-3500 you could install a 450 dirtbike motor in it and bore the motor out, and probably have enough to widen up your chassis!!!!

[400exrider707]

Originally posted by chevy400racer
im talkin 2500-3500 dollars in motor and carburation work here


why bother? I've bought running 450R's for less.

[AZ440ex]

I feel my motor is built! Just about eveything has been done. 440, porting, valves, cam etc..
Sure I can beat some 450's but they can spend $2500 and run away from us. Not to mention the benifit of being water cooled.
Spend money on suspension, train hard and beat them in the corners.

There is always going to be someone out there with more power.

[FASTDAD-77]

Yes you can build a 400EX to beat a STOCK 450R in a drag race. There is one that sits in my garage throughout most of the race season. Its a 440 stroker. Everything from the crank up is Powroll with an Edelbrock carb but reliability is an issue. Everytime it is raced, valve clearance must be checked and head gaskets are an issue on this one. You are money ahead to buy a 450R to race MX or cross country. The Atv was bought for around $3000 and there is 10 grand (plus) in this 400EX to make it run with a 450R with all the suspension and motor work and its lucky to make it through a race season. The power of the 450R is more manageable under most race conditions in my opinion and very reliable just to ride.
I'm not knocking the 400EX in any way because it is one of the best sport ATV's built between the time of the 250R and the 450R.

[boosted3g]

my stock bore has no problem with 450s in a straight line but if you would do the same thing to the 450 your going to be in the same spot as where you started. If you just looking to beat a stock 450r go with a high compression piston, stage 2 cam, full exhaust, 450r carb and run oxygenated fuel. Youll have plenty of power considering how short the wheelbase is on the 400.

[ohsobad_chevy]

All these replies thus far are accurate, but one thing that you have to remember, the quad is only as fast as the riders ability.
You say you are going to be racing XC......the 400 is a great woods quad!!
As stated above.... you will spend a lot more money on the 400 to make it equal a 450's HP, but you will sacrifice your reliability, which is what makes the EX so valuable. Just practice practice practice and those guys on 450's will be no problem in the woods.
;)

[FASTDAD-77]

If you want to make a 400EX perform and still be faifly reliable, air flow, compression and suspension is probably your best bet. You don't have to have huge pistons and cranks to make good horsepower and small bores give you a few extra bore and ring jobs for the future and its cheaper to bore a cylinder than bore and sleave a cylinder in most cases. In most cases like stated above, suspension is much more valuable than horepower in the woods. you can't go but just so fast in the woods before you hit a tree anyhow so handling is where its at. More important than anything is practice because if you can't ride, your gonna hit a tree anyhow!

400ex was made to be the "woods machine". Suspension is the key to being able to do what everyone else can. Throw in a slip on exhaust and a few other little things too and your set. Woods/Trails are mostly technical full of bumps and turns. Whats the sense of having all that horsepower when theres no room to gallop? I say start with an exhaust, air filter maybe a 450r carb, tires, suspension, and a steering stabilizer. Try that and if its not enough then start going crazy with a cam, piston, port and polish, maybe a bore. try things out instead of going all the ay to begin with. You may not all you think to keep up with others.