black smoke, bick firing, tan brown plug, WTF is going on, ex runs bad???

[400exBro]

lately due to the cold weather the ex has been runing tereble, it won't start as easy as last winter and runs worse... I put a new plug in becuase i noticed as soon as you let off the gas the engine will die, is this caused becuase it is to rich or too lean??? any ways, i cahnge the plug thinking it would fix it, pulled the plug and the tip was a tan brown colour.... put the new one in took it for a spin, still ran like crap...

What does it mean if it is shooting black, almost carbon black smoke out the exhuast???
and it seems to be poping all the way through the rpm range when it is not in gear, no load, am i too lean???

Tomorrow i am going to rip it all apart, clean the feul line, carb and feul tank and see how it runs, but i am also going to change the jetting...

also i am wondering about a different clip postion.. My buddy has a stage one kit installed in his ex with K&N fliter and a FMF power core 4 exhuast (old styly) everytime i ride it, the snap that think produces is incridable, mine has a soft feeling to it, same with the throttle( the feel seem smoth, and boring) where his seems to tightn up as you get closer to mid- top end, his will pick up way more than mine with the stage 2 in it.... I am wondering is the clip positon i notch higher on the needle then mine??????? i am wanting more snap, so could you help me out with the jetting so i am able to attach more snap then my pos slow, lay on throttle snap, it bores me man????

thanks for your help

[killed300ex]

sounds like your jeting is to rich bring it down a couple sizes
killed

[400exBro]

bring it down on the main jet or needle ??

i am going bring in the air feul mixture screw and see what happens.....

come on people i need some more info today so i can get it back to togerther and ride....

and i need more tips about getting more snap with out major mods???

[H400ex]

check the float and make sure its moving freely.

[hondaracer31]

That happened to mine also. Now I'm not saying this is what is wrong with your's, but on mine it turned out to be an electrical problem! It took me about 3 months to figure it out.

Some things to check, if jetting doesn't fix it, are....

make sure the ground is tight on the bat. and the frame,
make sure the spark plug boot is tight on the plug wire (the boot screws on to the wire, just like a bolt)

That's just my experiance on the subject, hope it helps....

[Rebel300]

This mite sound strange but the same thing was happening to my brothers Kawasaki Bayou. It turned out to be the charging system/Wiring system. It would back fire like crazy and throw all black smoke out until u charged the battery lol. I have no idea why but we just charge the battery and it runs perfect. So if its the same problem it has to do witht the wiring and/or the charging system.

[forum]

BRO BRO BRO. DO not downsize the jets!!!!!! IN cold weather the mainjet should be up sized. But jetting doesn't sound like you problem. It sounds to me that you need to warm it up. Try keeping it you garage(if heated) then give it a try. the weather lately has beed super cold (as low as -25) and 400ex's run like crap in cold weather unless you realy warm them up. But don't downsize the jets! in cold weather you upsize

[Colby@C&DRacing]

I agree it does not sound like jetting. As the weather gets colder the air is more dense and you need to jet up. Your problem sounds to in the eletrical system. If you are run an after market CDI put your stock one in and try that. Also as was said check all the ground connection and make sure your battery has a good charge.

[Mxbubs]

Theories, remember, just theories!

Backfiring-timing is a bit off?

Smoking-worn rings?

Discolored smoke-worn rings with water in oil?

Running poor-water in fuel?

Electrical-ha, good luck!?

What has changed on it from the time it ran good until the time is started running bad? The weather, gas, oil, etc...???

Let us know.

[Silverfox@C&DRacing]

One thing that I forgot to mention was that I have had alot of bikes coming in this year with water in the fuel. You might look at that, Try taking off the bowl plug on the carb and see if you can see a water drop in the bottom of the bowl plug. or drain your tank and put in some fresh fuel

[forum]

and say that. This cold weather we have been having could cause condisation inside your motor. this is what i'd do

Put your machine in a warmer place like a garage thats above 0 celcios

drain your gas and oil and put new stuff in(drain your carb too. by taking the bowl off or the bowl drainjet acces bolt)
check your ground conection of your wiring
check your airfilter and clean it
and if you do have a cdi change it back to stock like colby said

and while your messin with your carb. put in a litle bigger jet for safe measure but remmeber to change it back when it gets warmer again

[400exBro]

I hate jetting but i know how it is done.... any ways i drained the gas, cleaned the card from top to bottom, lowered the needle so it is rich, left main jet same, air feul mixture was turned down half a turn.. clean air filter, i am running stock cdi, the battery is at 12.57 volts which is good for a 3 year old battery... i am going to put a load tester on the battery, my ground is good check that out...

air filter is always clean, i clean after every ride, not as much in the winter, but i do clean it...

oil contains no water or anything...

after i done all this i took it out for a ride on my track which was covered in snow(wow) started easy, idled right off the bat, run awsome when it was cooled, i was actually able to get the front end up on snow grass... but after it got warm it started to run bad at LOW throttle postions, it would idle low and then die, and back firing when i am bogging it in low gear or i am barly on the throttle.. i am thinking it is the pilot jet range??? i am running a 42 pilot and stock setting, a 160 main, 4th notch on the needle, ...

i am guessing the black somke is coming from carbon build up on the WB exhuast, i am going to clean it and see if it still puffs...
Will removing the spark arrestor make it run a little richer???

I never thought about it being cold that it doesn't run right... I keep my ex in our shop and we ocasionly have a fire going to keep it warm but it gets realy cold down there fast.... and i barly drive it, maybe once or twice a month....

Man i can't wait to get a dale, no more freaking jets!!!!!!!!!! and i am able to do the work to the mapping and stuff ( yes i now how to do that, my dad taught me)

i doubt it is the rings becuase i don't see loss of oil or blue smoke.

it is running poor becuase of the cold weather, i know that for sure, like Colby said, air is more dense... it will run good if it is above -5 c but anything below that it will run poor...

any ways thanks for your help...

[forum]

instead of riding that 400 around start building a track, it will be hard seeing the grounds frozen but if you got a dozer its easy. after you got it built let me come ride it. lol:devil
Or if it snows let me bring up my new Ski-doo mxz REV.(dads:devil ) he wont mind

[400exBro]

ooo i can have that aranged !!!!

just give me a few weeks, i have exams next week and science isn t looking too good right now, i have to study... but i am sure i can have it arange :D

i bet you can find trails from your place to woodstock.... but gas would be a bit*h

o just wait till this summer, i am expanding my track.....

haha
lata