questions

[farmboy1]

quad has been running great. can't wait for this summer to be able to ride it more.

one thing i noticed is when i start it up for the first time in the day, choke turned on it smokes blueish smoke. i hate seeing this smoke as the last time i did my rings were shot. but after i ride for a little while and the choke gets turned off it doesn't do it.
is this just from being cold?

secondly, when it's cold it seems to knock alot and then doesn't knock near as loud once it warms up. is this normal

also haven't been into the carburator yet, but what jets should i be running with the mods below?

[farmboy1]

hello? anyone?

[vaget22]

From my experience if it smokes only at start up and stops when it warms up, its most likely valve seals. Not a huge deal. The valve seals are around the valve stems and keep the oil up in the head. When the engine cools and things relax a little, oil will seep past the seals and drip a little into either the intake or exhaust ports. This oil gets burned off when it warms up and should stop for the most part at that point. I would say it will get gradually worse over time but I wouldn't tear things apart for just that. As far as the jetting I would pull the plug and take a look at it. Next pull the carb and clean it real well and check the size of the jets. Next do a bunch searches about jetting in here and find a post with a bike with about the same mods as yours and that will give you a ball park idea. My guess with your mods would be a 152 to 155 main and 38(stock) to 40 pilot. There are a bunch of guys on here that know a lot more than me about jetting these bikes than I and someone will chime in eventually. As far as the knocking, without hearing it I can't help.

[farmboy1]

thanks for the help. me being new to quads, any little noise or puff of smoke freaks me out. also being tight with money, kind of makes me think of what i'm going to have to spend money on now. lol. thanks for the help

any other thoughts?

[slightlybent47]

Well it’s already summer here, 93* yesterday. I’ve heard that the ex is cold natured but mine is not, it will fire right up with just a bump of the starter. In fact I don’t even have a choke on mine at all. Even when it 30* out side it will still start right up on the first bump of the starter.
As for the jetting I would say that with the mods you have just bump the main jet one or two numbers. If it’s a 148 then try a 150 main and you should be good. You should not have to do any thing else.
If it is just smoking on start up and clears up within a few minuets then I wouldn’t worry about it at this time.

How often do you change the oil? That’s the key to keeping it in good shape, but I would get rid of the k&n filter and put the stock foam filter back on. That K&N will let dirt in and destroy your motor. There will be many that disagree and that’s fine that’s there opinion, but I feel very strongly that the k&n will do harm to your motor.

I’ll bet if you take a clean white cloth and run it up inside the air intake tube you will see dirt that has gotten buy the air filter.

I have a fully built 416 and have been racing it for two years and it still runs perfect and dose not smoke at all. But I change the oil every 3-4 hours and I still run the stock foam filter with a outer filter over that. And I never have any dirt come through the filter.

[farmboy1]

i change my oil every 15-20 hours. this seems to do good for me. if i haven't ridden it that hard then maybe a little longer. but if i go on a riding trip with my buddies, i change my oil as soon as i get back home as that is a long day of hard riding.
as for the filter, i'm going to keep an eye on it, and if i feel it needs changed then i will change it..

[bherriman]

With the mods I have I run a 155 main and 40 pilot. Since you have a full system I would start out at a 160 and see how it responds might end up needing 165. Go with the 40 pilot it helps it start so much easier I never use the choke either and it fires right up... as for the smoke he is right its probably valve seals if it stops when warm.

[farmboy1]

how long does it take to take thecarburator out of the quad to get to the jets. since the jets are on the bottom of the carb, i'm guessing you have to take the carb out everytime you tweak something. i would just like to see whats in it at the moment.

also it was about 75 degrees here yesterday, and i had to use the choke..

[vaget22]

First off let me hook you up with this. http://www.sendspace.com/file/wcy9is It is a free downloadable service manual for the 400EX. Click on the normal download or they will want you to pay $. It will describe the whole process of removing the carb and all of its parts. My shcool of thought is when I get a new to me bike I will pull the carb and make sure it is clean. Along with a lot of other stuff that isn't relevant here. I would take the time to pull the carb and clean it spotless and while you have it out you can record everything like jets and air screw position. Its good to know where you are starting from. It will take a lot longer the first time you do this as your learning the first time through. For me, I can get it out in less than a half hour. Go to Wallmart and get a can of their cheap carb cleaner and use the whole thing. It's like a $1.50 a can, heck get a couple. If all you want to do is just look at the main jet, there is a cap on the bottom of the float bowl that takes a 17mm wrench to remove. Drain the float bowl before removing as in the manual. With the cap removed you will see the main jet sticking down. Check the manual first and you will see what I mean. The stock type of jet will use a 6mm wrench to remove. There are also aftermarket jets that will require a screw driver to remove. Just depends on what you have in there. If you run into a snag post whats up and you'll get help. I've been on this site for about 8 months and these guys are a huge wealth of help and info.

[slightlybent47]

Yes vaget22 your exactly right, to take the carb off and clean and inspect it.
You can get to the main jet while it’s still on the bike but the pilot jet is too far up inside for me to get to without taking the carb off.
Don’t forget to turn off the petcock before you take the plug out from the bottom of the bowl.

If you change the main when it’s still on the bike just make sure you don’t cross thread the jet when you put it back in. and don’t over tighten the jet and break it off.