i want more power and you to help

[rdstoner]

ok i have decided to go with a bore kit and i was thinking the 416. but my buddy decided to make a bet with me while i do this he sadi that im not going to be able to make my quad beat his yfz 450 it beats a 07 piped and jetted. so i figured i will go with the 440. but i am new to this kind of stuff and love it so i need your help. i am going to buy a bottom end and just buy a bore kit that comes with the cylinder. now what kind of carb head and cam should i put in this thing and what else am i missing i think i will be ok with the stock crank but correct me if im wrong. so any help would be great.

thanks, Ryan

[liex21]

for a carb I'd go with a 450r one if you want to spend the money edlebrock makes a pretty nice one.Cam I'd go with a stage 2 hc and for the head a nice port and polish would def. give a nice increase in hp other things i would def. get are heavy duty studs and if youd like replace the valves,springs,etc just to keep it all fresh

[drew416ex]

If you want to beat him you need a stroker.

[Wheelie]

Originally posted by drew416ex
If you want to beat him you need a stroker.

Yup, what he said.

If you want to beat piped 450's it'll take some $$.

[rdstoner]

thanks for the parts list that will keep my mind open. when it comes to beatin him i can pretty much stay with him in the low end but when it comes to the top end he just walks me. but trails he cant leave me. so in order to get a stroker i would need just the crank on top of the bore kit right?

Originally posted by rdstoner
thanks for the parts list that will keep my mind open. when it comes to beatin him i can pretty much stay with him in the low end but when it comes to the top end he just walks me. but trails he cant leave me. so in order to get a stroker i would need just the crank on top of the bore kit right?

Basically you would make a 460 if you want to go nuts with power.

Split the cases, throw a +4mm stroker crank in that sucker. A clymers manual might help a lot as far as splitting the cases if you've never done it.

After that, buy the 440 cylinder. With the piston, because of the longer stroke, you still have to buy a 440 piston but a special one designed for the extra stroke.

Go for 11.1:1 compression, stage 3 hot cam, a really nice port and polish with +1mm oversized valves, all the heavier duty valvetrain components (rockers, etc) and HD studs.

That would be a HELL of a motor if it's set up right.

Oh, and when you're done, tell him you never did the bore or stroke. Just tell him you went higher compression with a cam:devil:

[tri5ron]

Originally posted by DMC-4OOEX
Oh, and when you're done, tell him you never did the bore or stroke. Just tell him you went higher compression with a cam:devil: Nah, just tell him you adjusted your valves, and filled it with premium gas. :D

[thebig450es]

Could you do a +7mm stroker?

[droppedmazda]

do a 460 stroker. screw the 11.1, go with 12.1 or 13.1 compression. dont do the oversized valves, you'll lose torque. and put a big web cam in with hardened rockers and hd head studs.

[drew416ex]

Originally posted by thebig450es
Could you do a +7mm stroker?


Yes, that is what the gt thunder stroker kit consist of. A 7mm stroker crank and 87mm piston which makes a 452. THe downside is they have to install it, they wont just sell you the parts.

[drew416ex]

Originally posted by droppedmazda
do a 460 stroker. screw the 11.1, go with 12.1 or 13.1 compression. dont do the oversized valves, you'll lose torque. and put a big web cam in with hardened rockers and hd head studs.

Are you sure you know what you are talking about? a 460 with 13:1 would be very unreliable. Strictly for a racer that can keep up with rebuilding the motor often. That would put lots of stress on so many parts. Yeah it would be quick, but not reliable. Also, strokers need to breath. The bigger valves help, not hurt.

[Glamis400ex]

why is everyone obsessed with "beating" everyone. Unless your running a straight drag all day...it's useless. Just ride the damn thing and have fun.

[rdstoner]

well i like how everyone is giveing me the options its keeping me with an open mind and all the diffrent things i can do. i also wasnt into beatin my buddy untill he said that my quad will never be as fast as his and i was like you know what i will just prove him wrong. i want more power just to show that the ex can be fast and fun and will hang with those 450s. i try and tell them that my ex hangs right with them through the trails and the only time they leave me is on the straights with top speed but i tell them a better handling quad will outperform at more powerful quad every time. and its just somthin to keep me goin bigger and bigger lol. so what would be the diffrence in the compression vs power like 11:1 gives this power and 12:1 gives this power? does the diffrent ratios give that big of a diffrence or is it just a little bit?

[BamBam730]

If you are going to invest all that money in a 400ex, why not just buy a new 450 of your choice. After all is said and done you are going to spend alot of money on the 400 and it will not be that reliable. You will be working on it quite often.

[Wheelie]

Originally posted by BamBam730
If you are going to invest all that money in a 400ex, why not just buy a new 450 of your choice. After all is said and done you are going to spend alot of money on the 400 and it will not be that reliable. You will be working on it quite often.

This isn't the case. A well built highly modded EX is VERY reliable. I built my engine in April 06' and haven't had any issues with it to date.

3 years and 4 months without an issue--seems pretty reliable to me.

[F-16Guy]

It's just a piped 450, it shouldn't be that hard to keep up with.

How about this if you don't mind running race fuel:

12:1 87mm piston (Moto Man - $165)

GT Thunder studs (GT Thunder - $115 installed)

Bore and Hone (Any competent shop - $75)

HRC copy drop-in cam (XRs Only - $189)

450r Carburetor (eBay, Forums - $100)

OEM or Cometic top end gaskets (most places listed above - $40)

[omeeomy]

i agree with glamis just ride the dam thing
if your not carefull itll hurt ya anyway
good rider in the trails beats a fast machine anyday

[justin1022]

ok well if i was you id put a JE 440 big bore kit with a 12.5:1 compression stage 2 hot cams crf450 cam chain 450r carb amr stage 2 rev box air filter run no lid put a 180 main in the carb and a good pipe and you should take him i had that exact set up and i could beat a stock yfz no prob.

[drew416ex]

Im with rdstoner. Im the same way. The more power, the better. We dont want a 450 because its way more fun to beat 450s on a 400ex. The expression on their faces are priceless even if you just keep up with them.

[Wheelie]

Originally posted by drew416ex
Im with rdstoner. Im the same way. The more power, the better. We dont want a 450 because its way more fun to beat 450s on a 400ex. The expression on their faces are priceless even if you just keep up with them.


I've had several 450 owners walk up to my quad and take a close look at it because they don't think a 400ex can run the way mine does. Before I built my setup I had several people tell me that keeping up with a stock 450 couldn't be done. A stock 450 doesn't stand a chance against me.

I love proving people wrong.