Low End Power???

[WheelieMan4]

I wasnt to sure where to post this at, but...

I just put in a 11:1 Comp. Piston and a Hotcams Stage 2, I have 20" tires, stock gearing (15/38 or 39), a 42 pilot jet, 160 DYNO so alot higher actually, moved the clip down one notch on the needle, and have the air/fuel screw turned out just about 3 turns...

Im starting to do some MX and I have like no bottom end at all...I'm going to get some 18" tires to help, but what else should I do...like drop a tooth in the front or maybe jet different???

Any comments would help, thanks!!

[400exrider707]

Your jetting is way off. Try messing with your main. I had almost the exact mods and even with stock gearing and 20" tires it still ripped the front end up like nobodys business.

[WheelieMan4]

do you think I should put my needle back first, or is that fine? also you saying im to rich? what size, in Keihen, would you reccomend me tryin...thanks

[GPracer2500]

Stock bore, right?

DJ160 is way too fat with your mods (unless your at minus 3000ft or something, lol). Depending on elevation, temps, airbox lid on/off, blah, blah, blah (gosh I get tired of saying that...:o ) I would start with somewhere around a K160 and probably work your way down. And put your needle back to the middle position.

There's a post in the How To section about how to set your fuel screw (and confirm your pilot circuit). A 42 and 3 turns out sounds pretty rich. I'm guessing a 40 at 2-3 turns out is probably closer. But the guide will explain the procedure for figuring that out.

[swva400ex]

mine rips on low end through mid.i am running a high comp. piston, stage 1 cam, 165 main, 42 pilot, with a full exhaust. i think the stage 1 has a little more low end. the main is a dyno jet not a keihen though.

[ohsobad_chevy]

Originally posted by swva400ex
mine rips on low end through mid.i am running a high comp. piston, stage 1 cam, 165 main, 42 pilot, with a full exhaust. i think the stage 1 has a little more low end. the main is a dyno jet not a keihen though.
That...In no way....helps this guy out....but thanks for telling us. :o :o :o

[swva400ex]

just letting him know what works for me. just saying that the stage 1 cam has more low end.

[WheelieMan4]

I didnt really want to have to move the clip on the needle again, because when I took it out the first time, I stripped them both pretty bad, the one I got out and the other one had no chance. So I drilled it out and the head broke off, so all I got holding it in right now is just 1 stripped screw...not a good thing but thats all I can do. I had a 160 K in before when I just had the slip on, k&n, lid off...and It didnt run good...I will put that back in now. I will keep that 42 pilot in, and just turn the screw in to like 1 1/2 turns or something, I wish you could adjust that when the machine was running, but its in such a bad spot. Thanks...

[swva400ex]

the position of the clip will be a big part of getting it right. get the screws out, run to the hardware store and pick up some new ones.just tryin to help

[ohsobad_chevy]

Yeah, those screws are really soft, I found that out the hard way myself. Replacements are easy to find at any hardware store, make sure you get the right threads. ;)

[WheelieMan4]

Got the 1 screw out and moved the clip up to the 3rd notch (middle) and went and bought a new screw...Then I went to change my main jet and when I took the jet out, I realized it was a 160 K I had in there the whole time...I thought it was a 160 DJ. I turned the fuel screw in some, to 1 3/4 turns out...Raining out so I could drive it at all...

GPracer2500 - I read your post in the How To section and then I went out to all my local hardware stores (4) and couldn't find ANYTHING that would work...I did pick up an actual air/fuel screw screwdriver...it had about a foot long bendable are before the tip...but all it had for attachments were like socket types, so that didnt work either...

Anyone else know what I should do?

[GPracer2500]

I use this one from MotionPro (second from bottom):

http://www.bikebandit.com/partsbandit/Tools~a~2670.aspx

I bought mine at Cycle Gear (they're a nation wide chain--might look for one in your area). I think MotionPro also makes an upgraded model that had a removable bits, including the "D" shaped bit needed for some newer fuel screws (like 05+ EX carbs).

[WheelieMan4]

I work at a dealership, and this weekend I asked one of the mechanics if they had one and he did, exact same one you showed me...

It worked great, so now I got a 160 K, 42 Pilot, clip on the middle notch, air/fuel screw 1 1/2 exactly...

Does that sound good? I still havent got around to drving it yet, but it sounded better at idle. Thanks alot!

[GPracer2500]

Originally posted by WheelieMan4
...so now I got a 160 K, 42 Pilot, clip on the middle notch, air/fuel screw 1 1/2 exactly...

Does that sound good?...

For average/normal temps and elevation, that sounds about what I would expect with your mods....If it's not perfect, it's probably very close.

[WheelieMan4]

Ok thanks alot everyone, especially GPracer2500...I will probably go riding during the week some day if I find time. I will let you all know how it runs then. Thanks!

[krt400ex]

Originally posted by WheelieMan4
do you think I should put my needle back first, or is that fine? also you saying im to rich? what size, in Keihen, would you reccomend me tryin...thanks

try a 158 or 160 Keihen jet. that should be close.

[honda460ex]

That...In no way....helps this guy out....but thanks for telling us.

Honestly, getting your jetting correct will help out. I don't think as much as what you are wanting. I'm sorry, but to ohsobad_chevy, swva400ex had good info about power. Just because you build something doesn't mean it's going to create amazing horsepower all over. You can sink $1,200 in a quad and it run like crap. You need the right combination of parts for your specific desire of power and where you want it. A stage 1 hotcam has a lot more low end than the stage 2. And I am guessing the original person to post is running a typical 11 to 1 wiseco piston. Bore, I don't know, but if it's stock, there is another reason you don't have the bottom end power you desire. I had the stage 2, 11 to 1 wiseco 406cc combo. Ran good, but it did lack low end power to me as well. I played with the jetting forever and a day too. Helped the problem some, never solved it. You have two things I would consider. 1st, go to a larger bore, 426 is a great choice, and 2nd, go with a higher compression piston or another brand, or both. If you do those two things, it will make a world of difference. Trust me, I have had three different built combinations in my 400 over the years, and a friend with a couple. We've experimented. Good luck... Motocross is awesome...