anyone notice a difference?

[08ex4]

my 08 400ex is piped, jetted, k and n filter, air box lid mod, choke removed, snorkel removed and hole plugged, and sparks 6 degree key and i havent noticed any more anything out of it. my buddies bone stock 05 400ex runs just as good if not better.... anyone know why? btw my plug looks great so its not a rich or lean issue and iv had the sparks key in out and back in again to see if it was the problem no luck thanks for any info

[yellow416ex]

have you checked your compression? I noticed a huge improvement with the sparks key, the throttle response and torque were amazing. I cant figure why all that didnt help build some good power

[08ex4]

no i havent. what reading am i looking for ive heard and read that good compression is anywhere from 110 to 120psi. is that right?

[Wheelie]

What jets are you running?

[08ex4]

155 main and 40 pilot at 600 feet above sea level the screw is out three turns

[dariusld]

Those are all great improvements. The only one I don't know about is the advance key. Did you install that?
How does it pull throughout rpm range? Does it stumble or miss anywhere?

[08ex4]

yeah i installed it. there is a good write up on here showing you how to do it but im not sure if its was worth it all it does is advance the ignition timing. it changed the sound of the exhaust but in my opinion thats all it did.it pulls ok throughout the whole rpm range but barely any mor than it did from factory maybe not any more it might just sound like it made a difference....idk

[TRXRacer1]

Originally posted by 08ex4
no i havent. what reading am i looking for ive heard and read that good compression is anywhere from 110 to 120psi. is that right? I'd have to look it up but you won't even get those numbers with the stock cam due to the auto decompression mech.

[bigd's ex]

With the pipe, rejet, K&N & lid removed you should see a definite change in the way your bike preforms. Just removing the air box lid will make difference. You almost have to have an issue somewhere. With all the mods you've done, you should see a night & day difference. Hope you get it straightened out.

[dariusld]

Originally posted by bigd's ex
With all the mods you've done, you should see a night & day difference.

X2

[thebig450es]

What should the compression be stock?

[Tommy Warren]

try a larger pilot the 40 is the stock size isn't it? I have a pipe and filter on my 300ex and I'm using a 42 pilot you should try a 44.

[thebig450es]

I don't notice any smoke but it feels like i should have more power. id try a 42 pilot jet i think 38 was stock

[TRXRacer1]

Changing the pilot isn't going to help.

[tri5ron]

did these conditions start happening right AFTER you installed the key?
are you sure it is in correctly, (not backwards), and are you sure you got the flywheel tightened down while "rotated to the left" (i.e.- rotated forward) ?

with the mods you have on your bike....
and if everything is installed correctly....

You should Definately be seeing/feeling significant performance improvements. No doubt about it.

Something isn't right here,
and it would be my bet, that it is something you are either thinking IS correct,
or something that you are overlooking..
go re-check everything carefully.

you should be having some impressive gains over stock.

[a4guy]

How safe is the timing key? Been thinking about doing that along with my pipe and rejet.

[tri5ron]

Originally posted by a4guy
How safe is the timing key? Been thinking about doing that along with my pipe and rejet. happy reading...
http://www.exriders.com/vbb/showthread.php?s=&threadid=349499&highlight=sparks+advance+guys+drain

[a4guy]

Originally posted by tri5ron
happy reading...
http://www.exriders.com/vbb/showthread.php?s=&threadid=349499&highlight=sparks+advance+guys+drain

Thank you! Great info.

[08ex4]

yeah its in right but i didnt notice a difference up till then so i put the key in thinking more fuel more air and maybe a more accurate spark timing should finally make it run better but even after the key install i noticed no difference. the second day i had my 08 i raced an 06 450r and stayed right beside him until i hit 4th then i slowly pulled away. mine was stock then and i think this 450 was ragged out pretty good but it surprised me that my quad ran with a 450 like that now after all the small upgrades its still the same outcome.

There's a bunch of things not right here.

First off, my 400ex was a completely different animal with just an exhaust, nevermind after I put the timing key in. Stock 400ex's are lame as hell. Mine felt like a warrior until I put those two on.

Secondly, there is no way you kept up with a 450r on a stock 400ex unless that 450 is way low compression and you weigh 50 pounds.. or he flat out sucks at riding.

[honda400ex2003]

something is def. wrong. you should be wooping a stock machine with that stuff. check everything, check the plug to see how the jetting is, then check the key to make sure the flywheel did not turn or something, along with checking for leaks and other things along the way. steve

[08ex4]

like i said dmc that 450 was pretty ragged out i later heard from some other guys we ride with. my plug is a little darker than it should be just a little lighter than a brown crayon. can i just turn the screw in a little to make it a little leaner or should i drop a size its a 155 main and the screw is 3 turns out? does anyone know if i would have to rejet for the 6 degree advance key. also when im just putting in first gear on idle and smash the throttle to wide open it boggs out and falls on its face but if i kinda pump the gas about 1/4 throttle 2or 3 time then smash it wide open it goes really well with no hesitation.....pilot jet wrong? im not knowledged enough to be able to tell what it is.

[08ex4]

one more thing could a small exhaust leak be the culprit to this issue? where the mid pipe slides over the headpipe it leaks there i can teel cause theres black stuff speckeled all over the frame in that area.

[thebig450es]

Id make sure everything is sealed up on the intake and exhaust, Also i think the jetting could be aliitle more spot on, i think you are close to it, but just need to take some time and play.

[dariusld]

Originally posted by 08ex4
one more thing could a small exhaust leak be the culprit to this issue? where the mid pipe slides over the headpipe it leaks there i can teel cause theres black stuff speckeled all over the frame in that area.

No

[MtnEX]

Well, I was pretty much feeling in the same boat as you after modding my 400EX. A pony or two just didn't get my blood flowing or make it quick enough.

It still needs some carb work it is getting though (and so does yours) but I know mine is not going to jump to life when this is 100% either.

You do need to correct this though....


Originally posted by 08ex4
like i said dmc that 450 was pretty ragged out i later heard from some other guys we ride with. my plug is a little darker than it should be just a little lighter than a brown crayon. can i just turn the screw in a little to make it a little leaner or should i drop a size its a 155 main and the screw is 3 turns out? does anyone know if i would have to rejet for the 6 degree advance key. also when im just putting in first gear on idle and smash the throttle to wide open it boggs out and falls on its face but if i kinda pump the gas about 1/4 throttle 2or 3 time then smash it wide open it goes really well with no hesitation.....pilot jet wrong? im not knowledged enough to be able to tell what it is.

First try a 42 pilot... and tune that in.
I think the fuel screw on yours is too far out too.

After that, if you are still on the dark side, you can try one size smaller main, or changing the jet needle position to leaner.

I think you should do the needle position first though.

Take the whole dang carb off without draining.
Point it away safely and work the throttle.

What you are looking for is the accelerator pump squirt.

Make sure you have one, and make sure it is shooting clearly all the way out of the carb.

If not, let me know

If so, move the needle clip leaner and try it out.

[08ex4]

thanks mntex the accelerator pump is working good so im gonna get a 42 pilot tomorrow and try that

[thebig450es]

Have you had time to play with the carb and running much ?

[MtnEX]

Originally posted by 08ex4
thanks mntex the accelerator pump is working good so im gonna get a 42 pilot tomorrow and try that

Do that and then tune the fuel screw out.

If it still stumbles, then try leaning out the needle.

You might want to pick up a 152 main when you get the 40 pilot.

[08ex4]

it had the 38 pilot in it could've swore i changed it but neway i put the 40 in and im going to start with the screw at 2.5 turns out we'll see what happens...

[Chet]

Originally posted by 08ex4
yeah its in right but i didnt notice a difference up till then so i put the key in thinking more fuel more air and maybe a more accurate spark timing should finally make it run better but even after the key install i noticed no difference. the second day i had my 08 i raced an 06 450r and stayed right beside him until i hit 4th then i slowly pulled away. mine was stock then and i think this 450 was ragged out pretty good but it surprised me that my quad ran with a 450 like that now after all the small upgrades its still the same outcome.

I finally got my 07 400ex running after cleaning the carb, it has a HMF pipe, Uni Airfilter and has been rejetted, it runs great, as for running with a 450 HMM, I rode a fully prepped dealer sponsored 450 Quad racer here on the east coast, the rider is in the pro class and he is 41 yrs of age and runs with the experts rather than running the senior class, he normally wins or is right there, but that quad is flat out scarey, pulls so hard it's hard to imagine a 450 can put out this kind of power, he is also an engine builder for motocross atv's ect, he goes by Hammer racing.

Chet