jetting 500 stroker

[panteramatt]

I have a fst 500 stroker 400ex with a ported head, cam, sparks x-6 pipe, aluminum airbox. Im putting an fcr41mm carb and need some jetting suggestions.Im in NJ at sea level and its about 45-50 outside.

[44oEX]

I have a 500 with 450R and run 170.

you don't have to jet to big with the 500. cause it pulls more gas in smaller jets,

[EPDP99]

im running a 45p #5 clip on needle and a 185 main in my fcr41. thats a 465 stroker

[panteramatt]

Hey 440, did you see a big increase with the 450r carb? Im trying to decide to either put this fcr41 on my 500ex or put a 450r carb on that and put the fcr on my z400.

[44oEX]

yes there is a pretty good diffrence in power from the stock carb to the 450R one. the thing is the 450 carb will not just bolt on. there is a little work involed.

here we did a couple post on this subject. Here you go.


http://www.exriders.com/vbb/showthread.php?s=&threadid=142331

http://www.exriders.com/vbb/showthread.php?s=&threadid=143853

[hondatv]

I'm running a FST 502 kit 11 1/2 to 1 motor with big valve head, TC cam, x6, fcr 41, K@N powerlid and K@N filter. I have a 50 pilot, air screw 1 1/2 turns out, needle on 3rd clip and a 195 main at sea level. Start big, be safe I lost a motor due to lean conditions with a 170 main Mickey's recommendation (on stock carb).

[cals400ex]

is the 450r carb shorter than a stock 400ex carb in length? it just looks as if they barely make it to the air boot on the air box?

[44oEX]

Originally posted by cals400ex
is the 450r carb shorter than a stock 400ex carb in length? it just looks as if they barely make it to the air boot on the air box?


well the carb is a little sorter but it`s no big thing. it`s not taht much sorter.

the reason it looks like the boot is not going on all the way is that the 450R carb has a longer neck or wtv you want to call so the boot can`t go all the way. but it still bottoms out. there is as much in the boot as there would be on a 400ex carb so don`t worry about it. just make sure the clamp is tight

[cals400ex]

did you pull the air box forward or just leave it in the stock position? also, easily does it want to die when it is cold out? i am looking into one for my friend and i don't want this to be a PITA to start, idle, fit properly, etc. for me it is no big deal but for him he won't want to touch it but just put it on, jet it, and go. thanks for the help.

[44oEX]

You don`t have to move the box but you could if you wanted. but it will work good even if you don`t as for the starting ones you get the jetting in the ball park it starts good and idles smooth. And I have a 500 stroker with really wild cam.

Ones you do all the work to make it fit right it works really good and it`s a cheap way to get power.

read this it sould anwser all your Q?


Originally posted by 44oEX

Some people just warm up the intake boot with warm ( boilling water ) and then jam the carb in there. it might work but that will pop out. So don't do it

The right way to do it is like yfz450admirer said ( i told him how )
take the intake boot off of the motor. then use a dremel or sand paper ( slower but cheaper then a dremel lol) or grinding rock on a drill or something, and make the hole in the boot a little bigger. don't go to big. On mine I still have to fight it a little to make it go in but it's just cause I got sick of sanding :D . ones you have the hole the size you what ( make sure it's round so it won't leak ) put the intake back on the motor then work on the boot that goes from the air box to the carb. That one is a little harder cause it's only a thin wall, so you don't want to take to much out. Take out a couple mm if you can force the carb i then you good.

One's that is done you basicly done. see it's not hard it just takes a little time to get it the right size. The only problem I got was that the stock choke lever ( 450R ) it will NOT clear the gas line ( use the 450 one just cut it a little sorter so it won't kink. and use a small clamp to hold it on the petcock) The choke thing is not that big of a deal. you don't need it for summer riding. I have to have one ( I made a costom one ) but it's only cause the winter wheater is around -10 to -20

You can use ( you have to ) the stock 450R gas cable with the EX's trottle.

Know for how it runs. well yes Rico if you give it gas when it's warming up it will stall. But that is kind of a good thing. you have to let the motor warm up before you ride anyway right.

But as you don't have to give it any gas anyway. unlike most quads I've seen, one's it starts it will run on it's own with no gas and it won't stall on it's own. ( if you jetting is any good ). Mine runs really smooth on idle. and it's a 500 stroker with a wild grind cam. so it sould be even better on a normal size motor ( 400-440)
and the idle is smooth from cold start up all the way up to the end of a couple hour run.

One's the jetting was good the trottle risponce is really good. I can give it full trottle when idling and it will rev up right away. as long as you pilot screw is set properly you won't have any problem. if it's not well then it will complain a little but I mean it's normal if the jetting is off.

speaking of jetting. I was having trouble with the stock carb on the 500. I could just not get it like I wanted. it was always complaining. well the 450 carb is easy to jet and even if you are not spot on with the main or needle it's no big deal. ( well it is but I mean it will still run good so check the plug. )

And as for falling of I didn't have any problem yet. and this is not a show quad it is riden hard. and no dunes it's a rough trail and pit ( jumps ) riding. just make sure the boot is not to tight. And put the clamp pretty tight. but I would not worry about the carb falling off.

I think I awnsered all the Q?'s if I misted any let me know.

oh and for jetting start of with a stock pilot jet and something around 170 for the 440. then work from there.

custom choke

http://www.imagestation.com/picture/sraid153/pcd6b18360272bc6298a177229d033903/f5919b89.jpg

side. you can see the sorter gas line and the clamp I used. And how tigh the choke is
http://www.imagestation.com/picture/sraid153/p72ee5b2348811cf076dd64a6737e4437/f5919b83.jpg