440 kit installed NOW WHAT JET SIZES?

[ryanowarrior]

installed a 440 kit on my buddies ride, so the question is whats some idea's on where i should start with jettin? got a full exhaust and UNI filter with K&N lid. thanks

[atvrider13]

between 170 and 185. Im not quite sure with the k&n lid maybe 175

[hondarider421]

i ran no lid a fcr and a 440 big bore with stroker crank and i ran a 182 with a 48 pilot and she ran amazing id say depending on ur carb anything from 175 main too a 185 main and a 45 pilot to a 50 pilot good luck man

[CJM]

Id start at a 190 if you can find it, failing that a 185.

[hondarider421]

wat carb are u running specially if u need a 190 my built 450 dont use a 190

[CJM]

Start at the highest you think you will need and go down. 190 is the biggest therefore start there.

Also a plug chop would be a good idea.

[hondarider421]

its a 400 ex man at most a 185 but i see wat ur saying its deff a good start but if he is running a reg carb he will be way to fat it dosent draw enough air

[CJM]

Oh I totally agree. But like I tell everyone when it comes to jetting: In some cases depending on climate, elevation and mods what works for one person will not work for another.

So that being said, you usually want to start at the largest jet you think you may need and end up at the one that gives the best plug reading. I know many that use a 185, 182 or a 180 main on a 440.

In some cases however it just doesnt make sense: EX: mine has the mods listed in the signature, I used a 170, was a tad rich but I was happy b/c I rather be rich than lean and I dont have to mess with it for the temperature changes. Point is that others used larger or smaller jets with near the same setup, so you just never know.

[hondarider421]

yea i see and ur right i deff agree plus i was running a 460 not 440 but i was useing a fcr so my jetting would be much diff lol ur right i was just trying to see y u said that but great explination thanks man srry for the hastle

[ryanowarrior]

dang thanks for the info guys!!! all i have at the time is a 170 so i was gonna see what that did...but wasnt sure at all on the poliot..and its using the stock carb

see some are using the 450r carb, and info on that? and the reasons for using one? thanks again for the fast help :D

[hondarider421]

well my input on the 450r carb is more fuel to air ratio as its larger carb inlet and all and they are cheaper than a fcr and id say a 45 pilot starting and two and a quarter out on fuel screw and if not idleing right turn fuel screw out a lil when u hit three turns out go up to next size thats how i did mine but i deff advise goin up to a 450r carb

[CJM]

Best way to set up your carb is as follows:
EX carb: start as high as you want. 190 may be a bit much as already discussed-at least start at a 185 main. Use a 42 pilot, will be fine for you and your setup. Fine tune using air/fuel screw.

450r carb (only can use style 04-05 carb); This carb allows more fuel in, its like adding larger fuel injectors to cars-more fuel with more air=more power. Jetting is usually quite close to what a 400ex carb will be, pilot you want a 52.

The main thing with the 450r carb is you will need to fab up or buy an adapter to fit it on your airbox boot (member zrpilot makes some nice aluminum ones), a 450r throttle cable, and a hotstart block off. The reason for the larger pilot is b/c you cant use the choke lever to well due to the nature of the EX's gas tank design, larger pilot allows for chokeless starting.

If you go the 400ex FAQ at the top of the forum theres more info there.

[hondarider421]

oh one other thing ull need to trim a little off the adapter on the back of engine but good luck man ull have a fun machine when ur done

[ryanowarrior]

thanks alot guys for all the help!!!!!!!!!!!!!!

[hondarider421]

Np man good luck and have fun

[ryanowarrior]

well started her up tonight everything seemed good....after a couple of minutes of runnin started to here i high pitch whistle kinda when ya stab the throttle...come of find out the head/headgasket isnt silled all the way down in one corner...dunno why, it was tricky gettin it on there and we figured the head bolt would pull it on down, but i guess it didnt...guessin its something with the dowl pin not seating right. any idea's

we started off with a 170 main jet and still waitin on the poliot jet to show up....anyways we are gettin there should be fun ride one day :D

[CJM]

Something isnt right if the headgaskets not seating.

Id take it apart and see if you can make it snug down.

[ryanowarrior]

Yea ended up bein a problem with the top of jug surface not being 100% flat causing the gasket not to seal in one corner...gotta fix this now somehow..

[CJM]

Gonna have to mill the jug.

[JOHNDOE83]

FYI, 400ex with a 440 will seem to run fine with minor jetting adjustments, to accurately get the jetting down you will need to do plug chops or even use a o2 sensor.

I have a 440 that uses a 220 main jet and a 52 pilot.