400ex not right after mods...

Hello,

I need some guidance. I added the K&N Power kit last week, removed the snorkel & air box lid, which made a big difference. Today, I added an aftermarket slip-on exhaust (Stroker). I changed the jet to the 160 after I added the K&N Power kit, today I changed it to 165 when I added the slip-on exhaust, as the directions state (I am at 3,500ft elevation).

My problem is: when I get on the throttle hard, whether in nuetral or riding it, it cuts out. I tried going with the 160,165 & the 170 jet and it made NO difference at all. I am at the point to take it to the dealer and have them fix it, but I would rather do it myself if possible. I have went through the dyno jet and K&N directions several time, but all was done correctly, to the best of my knowledge.

The only thing I haven't checked is the valve clearance, as I adjusted them last week when I did the K&N Power kit. Could I have tightened them to tight or left them too loose to make this problem happen?

I would appreciate any help or info.

Thanks,

[Castor-426ex]

does it sound like your rev limiter is kickin in??

Originally posted by Castor-400ex
does it sound like your rev limiter is kickin in??

Castor-400ex,

I am not sure. A buddy that was helping me doesn't think so because it doesn't run as good as it did without the slip-on exhaust. I don't think it's reving as high now as it did before I added the slip-on exhaust.

[Zero Z400]

I'm not sure but u still sound rich

[VegasEx'r]

You removed the snorkel & airbox lid, but the air box is still there, right? Does the engine act like it's going to stall, but doesn't (but it does come real close?)? If that is the case, have you checked to make sure that the air boot on the intake side of the carb hasn't come off? That happened to me once, and my quad behaved the way you are describing yours.

Originally posted by zero
I'm not sure but u still sound rich


zero,

So, if it is running rich, do I increase the size of the jet or decrease the size. As I stated above, I have tried the 160,165,170. The 170 is the highest number in the dyno jet kit that I have. If I need a higher number, where can I pick one up from?

Thanks,

Originally posted by VegasEx'r
You removed the snorkel & airbox lid, but the air box is still there, right? Does the engine act like it's going to stall, but doesn't (but it does come real close?)? If that is the case, have you checked to make sure that the air boot on the intake side of the carb hasn't come off? That happened to me once, and my quad behaved the way you are describing yours.


VegasEx'r,

Yes, the air box is still there. It doesn't seem like its gonna stall, it seems to me like it's not getting enough fuel or too much fuel, it just cuts out if I get on it hard. I really don't think it's the rev limiter, because it doesn't seem to rev as high as before. The air boots are on tight to the best of my knowledge, but I will verify in the morning.

Thanks,

[VegasEx'r]

If the boot is on tight, then you are probably too rich, so you want to go down on the jet size. One more question: Does it stutter right when you hit the throttle, or is it delayed a few seconds until you have the throttle pinned?

Originally posted by VegasEx'r
If the boot is on tight, then you are probably too rich, so you want to go down on the jet size. One more question: Does it stutter right when you hit the throttle, or is it delayed a few seconds until you have the throttle pinned?

VegasEx'r,

It responds excellent from closed to 3/4 open throttle. It starts to stutter when I have it between 3/4 and wide open, mainly at wide open. What jet size do you think I should be using?

Thanks for your replies,

[VegasEx'r]

I'd say a 160 or 165, but you have tried those & had the same problem. I guess you could try a 155 (if you have one). Take it out for 5 min. or so & then check the plug. This one has me kinda stumped. Let me know how everything goes when you work on this.

I've got one other question (off topic). If you don't want to answer, that's fine. I see you work for Ford & own a couple PSD's. Do you think Ford will EVER acknowledge & /or fix the cackle?

Originally posted by VegasEx'r
I'd say a 160 or 165, but you have tried those & had the same problem. I guess you could try a 155 (if you have one). Take it out for 5 min. or so & then check the plug. This one has me kinda stumped. Let me know how everything goes when you work on this.

I've got one other question (off topic). If you don't want to answer, that's fine. I see you work for Ford & own a couple PSD's. Do you think Ford will EVER acknowledge & /or fix the cackle?


VegasEx'r,

I do have a 155 jet, I will try that. Speaking of the sparkplug, I tried to remove it already and can't seem to get the tool to lock on it. I even tried a craftsman sparkplug socket and it won't lock on to it either, I guess that's another project.


As far as the "cackle" issue, I doubt ford will do anything about it. There is a guy over on the www.ford-diesel.com forum that has came up with a fix, you may want to check it out if you have a Ford PSD.

Thanks Again and I will followup with the solution, if I find one.

P.S.- Maybe I should just trade it in on a Raptor, just kidding ;)

[VegasEx'r]

Originally posted by BWilliams

P.S.- Maybe I should just trade it in on a Raptor, just kidding ;)

Yeah, I'm thinking about gettin' a Duramax, same as you are a Raptor. ;)

I'm "playing the game" w/ Ford right now, & i'm afraid I already know the outcome. When that happens, I guess I will do the Hutch mod (i've been watching those thread over there for some time now). Just stinks about the warranty.

Let me know what happens w/ the 155 ( I would think you'd have to be lean).

[Leo]

this may / may not apply to you, but after installing my slip-on I thought my 400 was breaking up on top.. turns out I was hitting the rev-limiter.. (I would have sworn I wasn't) the only way I found out for sure was with a buddy riding his quad behind behind me :D It sounded like it was sputtering while riding, but if you were behind it you could hear the distinct 'hitting the rev-limiter' sound..

Leo

[SUPERFLY 400]

When you installed your K&N filter, make sure you didn't over oil it. Too much oil in your air filter will make it bogg out and studder when giving it throttle. Sometimes when there is too much oil on your air filter, the excess oil will drip and fill up your rubber catch (what ever its called) at the bottom of your air box. Check that before switching out jets.

[400exBro]

Superfly 400, i think that was my problem i have had filter oil, lots of k&n oil at the bottom of air box, and i thought i was running rich, today when i oil i'll make sure to do a little at a time till no white spots apear.........
Do you thinks that over oiling will affect the profermance of the machine???
thanks a lot dude
Bro

[SUPERFLY 400]

It happens to the best of us! Live and learn. Over oiling your air filter will definitly effect your performance. Your engine cann't breath with all that oil.
Good luck and HOLD ON:D

[400exBro]

thanks you saved me the time trying to adjust my jets and everything else.
Bro

Originally posted by VegasEx'r
Let me know what happens w/ the 155 ( I would think you'd have to be lean).

VegasEx'r,

OK, I am going crazy now :confused:

I tried the 155 Jet, no difference. I put the snorkle and air box lid back on, no difference, I re-adjusted the valves just to verify that I didn't over tighten them, they were perfect.

The only thing that really bugs me is that when I changed the different jets, put the air box lid back on & put the snorkel back on that it stayed the same, no difference that I could see. When we jetted it, when I put the K&N power kit in, I had the 155 in 1st, it didn't run right, so I went to the 160 and bingo we had it.

I am the type of guy that gets frustrated VERY quickly, so, I guess my next thing to do is to see about getting a 'rev limiter', as Leo suggested, to see if that takes care of it OR you guys will see it in the 'For Sale' section this week ;)

Anymore suggestions??

[VegasEx'r]

Weird. :confused:

I didn't know that over-oiling the filter could cause problems. Do you have the stock filter still? If you do, throw that on & see if it still happens. BTW, what clip is the needle on?

Originally posted by VegasEx'r
Weird. :confused:

I didn't know that over-oiling the filter could cause problems. Do you have the stock filter still? If you do, throw that on & see if it still happens. BTW, what clip is the needle on?


VegasEx'r,

Last week when I added the K&N Power Kit I just stuck the air filter on, it seemed to be oiled as it should. I do still have the stock filter, I will try putting it back on.

The needle is on the 3rd clip as the directions say. Should I try to move it to the 2nd groove?

This is getting old real quick.

Thanks,

[MichaelS693]

i agree with zero it sounds like you are rich.....decrease the size of your jet

Originally posted by MichaelS639
i agree with zero it sounds like you are rich.....decrease the size of your jet


MichaelS639,

I am currently using the 155 jet, are you saying that I should try the 150?

Thanks,

[VegasEx'r]

What pipe did you say you were using? Is it a full exhaust or a slip on?

[Wheelie]

Leave the airbox lid off. You're running too rich, for your elevation a 150 or 152 main jet should do the trick. If it runs good to 3/4 throttle, leave the clip on the needle where it's at (3rd groove as stated before).

IMO--Ignore the spark plug, go with seat of the pants feel, jet it where it runs best. After each jetting change, run it for 20-30min, that way the true story of whether or not it's jetted right comes out to play.

Why the K&N power kit recommends a 170mj with only a pipe and filter, I will never know.:huh

Good Luck!

[gojk]

When my bike was doing close to the same thing, I cleaned my air filter first then I went from a 165 MJ to a 155 before it ran right, also it stumbled hard when I nailed the gas so i moved the needle to the second notch and that made the biggest difference in throttle response. It you are lean on your MJ it makes your bike top out of every gear really fast and it feels like the bike just seems flat at the top end. There is a really go article on jetting inthe dirt wheel mag Apr edition I believe. It really helped me.

[Honda250XRacer]

well that doesnt sound very good somethings not right might be your jets try 155 or if that dont work try something else....thats all the advice i can give ya man ....just tryin to help
LATER :D

[Honda250XRacer]

yea yea try a 150 or 152 for your elevation i think you would need to decrease

Problem Solved :) :) :) :)


As you can probably tell, I am a happy camper :)


I took Leo's advice about checking to see if the problem I was having was the REV LIMITER and that's what it ended up being.

I ended up calling around for about an hour this afternoon and found a motorcyle shop that was open, Chaparral Motor Sports. Being Sunday, not many were open. They had the best price, out of the 3 that were open. The $129.00 was the best money I have spent so far.

I ended up with the WB Rev Box. From all the negative feedback on it I had my doubts, but at the point I was at, I figured it was worth a try. In my opinion, I see a VERY noticable difference with the WB Rev Box installed. The throttle is more crisp for starts. I guess the Stoker exhaust I bought is a full blown race silencer, I was not aware of that. I read in other posts that with the WB Rev Box guys/gals were having problems starting their quads after installing it. Mine started right up, I didn't even use the choke. I guess that;s one of the benefits of living in Sunny California ;)

I rode it for about an hour or so earlier with the 155 jet in it, should I change the jet back to the 160 as K&N suggests in the install directions, or leave it be? I guess I can pull the spark plug and see if it's running too lean and go from there??

Anyways, I would like to thank everyone for their assistance in getting me through my crisis


Thanks Again,

[Leo]

so you think you were hitting the rev limiter before..?

it's funny how it sounds / feels so much different after you add a good loud slip-on...

Leo

[yellow_ho_01]

i think my problem is alittle different..... mine runs fine,... i can sit there and nail the throttle(in nuetral) and it revs out just fine... and does just fine in about 90% of the drag race type takeoffs... my problem is that say i go into a corner in a gear thats alittle high, it cuts in and out like(sounds the same as when you run out of gas, cuts on and off) but as soon as i downshift it works right, most of the time. I just got this 400 like 2 weeks ago, i checked everything out on it.. its got a 165 in it now,.. screw is at 3 1/2, i tried it at 2 1/2 but it did the same thing(of course) i checked the needle, now correct me if im wrong, but doesnt the needle in a jet kit usually have the size and other stuff marked on it?? this one has nothing on it at all.... the only time it does this is if im in a gear just alittle (should still run, maybe bog down, not cut out) high and i nail the throttle.... like its not getting enough gas..or maybe too much... OH another thing... until the quad has been running for like 2-3 mins.. when you punch the gas it blows alittle smoke,.. only when you punch it though... i was thinking this might be to rich... and also be tyhe problem for the cutting out,.. too much gas

Originally posted by Leo
so you think you were hitting the rev limiter before..?

it's funny how it sounds / feels so much different after you add a good loud slip-on...

Leo


Leo,

I honestly didn't think I was hitting the rev limiter, but after the swap, the cutting out is gone. It does seem to need a re-jetting now though. It feels like it did when I added the K&N Air filter without changing the jet, but slightly noticable. I will pull the plug before my next ride and see how it's burning. Besides that, the dang thing is running GREAT

Thanks Again,