Lexx pipe uni filter jetting

[bjh05400ex]

Hi guys I'm fairly new to the atv scene. I've got a 2005 400ex and I have installed a new lexx slip-on with uni filter. I am undecided on if I will run the air box lid on or off. I picked up a new 42 pilot jet but I am not sure what I should use for the main or where to set my air/fuel screw.i am using keihin jets if it makes any difference . I found that my needle does not have adjustable notches on it. Can I get this thing to run good without an adjustable needle or do I need to pick one up? If I need to get a new needle will any model years work? I live in wi by the il border Maybe some of you local guys can give some feedback on my jetting questions and also whether I should run lid on or off.

[Zakradu398]

I personally would run no lid, you'll want to clean the filter just about every ride though.

As far as jetting that 42 will work and depending on how cold it gets a 45 may even work(did for me with similar mods). As far as the main jet I would get between 162 and 155. You should be in there.

The needle changed in the newer 400s to be in adjustable, with all my mods I believe I only raised it a clip so you should be OK there.

[i973eat1]

On my 2001, I am running a 42 pilot with a 160 main (with the lid on) and have no problem. Are you by the MO/IL border? Question is where you will be riding as to whether you should keep the airbox lid on or off.

[Zakradu398]

Where you're riding IMO doesn't matter. I ride in some of the worst conditions, snow, MUD, creek crossings, slate dumps, etc. and I've never had a problem directly related to running no lid. If you plan on riding in sand though (I never have), I would run an outerwears lid or the homemade equivalent.

[bjh05400ex]

Thanks of the info guys. I will try the lid off but I think I am ultimately going to get one of the EHS racing lids. Im sure I could make one myself but I definitely could not do it as pretty as they did. I will mostly be riding on some property my inlaws have so mud, dirt, dust and snow are the main conditions I will be dealing with. As for the Main jet I am going to run this weekend and pick up at least a 155 and a 158 to throw in there and see what happens I guess. As for the needle all I saw was one standard spot for the clip but maybe I didn't pay that close of attention. I973eat1 I am on the border of WI /IL its like a 3 hr drive to the MO/IL border. Is there some good spots to ride by you?

[bjh05400ex]

There has to be more guys out there with the same mods that are in the midwest region and can chime in on what they are running.

[i973eat1]

I am right on the border and there is St. Joe State park is about an hour away from me, which isnt bad to ride. A lot of small, loose gravel and sand, the trails are pretty rocky also. Then there is Finger Lakes in Comumbia MO, that place is fun to ride at, tons of trails, a lot of nice trails and mud also. That is just about 2 hours away from me. I know that there are some other places to ride on the IL side also.

[bjh05400ex]

Ok guys here is an update now that I have had some time to work on things. I got my lexx pipe installed added the uni filter with a outerwears cover, modded my air box lid with a 6"x4" square removed, installed the 42 pilot and a 158 main jet turned my a/f screw approx. 2.5 turns out. I am at about 850Ft above sea level and I do not have an adjustable needle at this time but my buddy did shim it to raise it slightly. I do get cold weather and its approximately 25F here now. I was in my semi heated garage temps around 45F and was having a hard time getting her started. once she finally fired up I had to hold the throttle slightly to get her to stay idling till she warmed up. once warm she will kept an idle. what am I missing here? It got late and I didn't really get to make a run to do a plug check. Just worries me that its a bear to start as I thought I would have solved this issue with a 42 pilot. Any suggestions would be appreciated.

[2001400exrida]

i ran a lexx slip on with lid off and for me the 42 was just too rich, i know many have great luck with the 42, but i was getting black plug after firing up a brand new plug, and my idle was rich, if i let it sit there and idle, it owuld idle but after a couple minutes it would get slower and slower and die. too rich....

i went with a 40 pilot and a 165 mj with a lexx pipe and lid off.

[bjh05400ex]

i ran a lexx slip on with lid off and for me the 42 was just too rich, i know many have great luck with the 42, but i was getting black plug after firing up a brand new plug, and my idle was rich, if i let it sit there and idle, it owuld idle but after a couple minutes it would get slower and slower and die. too rich....

i went with a 40 pilot and a 165 mj with a lexx pipe and lid off.

thanks for the input what elevation are you at?

[2001400exrida]

flat lander here, i think we're around 600-800ft. so basically sea level. also just a bit of info on the lexx, it's a good idea to use some RTV silicone where it connects with the midpipe, the instructions explain it too, but it will leak if ya don't......you can see in my pic here where i put the silicone, it's orangeish red

http://i102.photobucket.com/albums/m93/rschaef83/IMG_0007.jpg (http://s102.photobucket.com/user/rschaef83/media/IMG_0007.jpg.html)

[bjh05400ex]

thanks for the heads up on the RTV I did use that during my install. I also added an exhaust clamp where the lexx mid pipe connects with the stock header. are you using Kiehin jets?

[2001400exrida]

yup keihen jets, and i did the same thing with the exhaust clamp. it's a great pipe, but as you now know the fit and finish does require a little touching up. overall though i ran it for a couple years and loved the pipe, you can really quiet it down if you leave that spark arrestor in it, once it's out though the thing is loud!

[bjh05400ex]

Yeah I'm pretty happy with the pipe so far. I have not really had the chance to ride with it and get on it tho. I will pick up the 40 pilot this afternoon and try installing it tonight along with changing from the 158 to a 165 like you have to see if that helps things. Where you located do you get the cold winters as well? mine seemed to idle alright once I got it started with the 42 and a 158. I just had a bog every once in awhile when I tried to crack the throttle. I will also check my plug out.

[2001400exrida]

we get pretty chilly here, probably not as long a winter as yours, but yeah it's 20-30's most of the winter, I try not to ride if it's below 20, lol.

that throttle bog happened with my 42 as well. right at idle if I pressed the gas a little too quickly it would just die. Adjusting the a/f screw can also help you get it tuned in better, most people are able to tune the 42 pilot, for some reason i didn't have such luck. I was able to run my 40 pilot at 2.5 turns out on the a/f and it never bogged.

[Mtndew99]

I think I'm the only person that never had a problem when it was cold out with a 400 I don't use the choke I just pump the throttle once or twice after I turn the gas on and hit the start button and she starts and idles

[bjh05400ex]

a little update as to how things are going. I change to the 170 Main wand kept the 42 pilot A/F screw 2-1/2 turns out. she fired right up and all I had to do was adjust the idle slightly. Unfortunately I can not check my plug as the Honda issued tool ended up rounding off on the inside. I ordered the motion pro socket that is designed for these bikes and it will be here tomorrow. I can say holy cow what a gain in throttle response and power. Im a 240lb guy and im doing roll on wheels in 2nd now with a light snow dusting on the streets. Before I had to clutch them to get it up. I would recommend these mods and pipe to anyone looking to gain some power and not spend a small fortune to get it.

[bjh05400ex]

We'll I pulled the old plug that had been in it since before my mods and it was a dark black. Put in a new one and did a run to check plug color and it it came back white. In fact while mid way into 5th gear the bike bogged and then died. I let it sit for a minute and tried to fire it up three four times before it cranked over. I limped her home and put her away. I'm lost here on getting this jetting correct. I'm thinking I may need to buy a new lid and try that or do you guys think I can get it dialed in with the modded lid? Btw it's 24f here today. I know temps can be an issue for proper jetting.

[bergoff]

I don't live to far from you and have the same pipe. I've always ran with lid on and witb the spark arrestor out I would get back fires. My pilot is 38 155 main. I just bought a 42/165 since I ride more in the winter. My plug looks good but I still get some decel pop. I wont get the new jets installed until Thursday or so. Are you running without the s/a?

[bjh05400ex]

I don't live to far from you and have the same pipe. I've always ran with lid on and witb the spark arrestor out I would get back fires. My pilot is 38 155 main. I just bought a 42/165 since I ride more in the winter. My plug looks good but I still get some decel pop. I wont get the new jets installed until Thursday or so. Are you running without the s/a?

I am running with spark arrestor in. I worked on the jetting all morning Saturday and had to go up to a 195 main and I have a 42 pilot and
2-3/4 on A/F screw. In 3rd when testing for pops on decel it only popped once compared to other jet setting where it popped multiple times. after checking my plug the ceramic is a noticeable mid to dark gray color to it. From what I read grey to tan is normal for the plugs. if anything im running rich but to me that's a good thing compared to lean. trust me I am no ace mechanic but I do use common sense. everything I have learned has come from reading the forums, talking to other people with quads or bikes, and from speaking with service techs. I hope I have it right because its becoming no fun when everyone else is riding and im stuck in the garage tuning lol.

[bjh05400ex]

Bergoff

I think you are prolly on the right path with the 165/42 jetting but you may want to get a couple different sizes while your at it. I would say to get an outerwears cover for your filter and run either no lid or a modded lid. pm me with your cell and ill txt you some pics of what I did. the outerwears cover was like $15 from rocky mountain atv and obviously the mod to my airbox lid was free.

[MtnEX]

Where I see most hair pulling on jetting is aftermarket non-carb brand jets and once in a while a needle issue. Dropped needle. Needle out of a carb kit, blah blah... etc.

Just dying... problems with the relay... because main power runs through there. I have seen them crank over OK but not start back.