I would not waist my money on Dyno jets. I would just buy some jets and go for it. I just got my 06 400ex and I put a EHSracing lid with outerwears on it and a
a cap with spark arrestor for the stock pipe. The cap eliminates the old cork spark arrestor and gives the bike a more throater sound. I am about 500FT above sea level and I rejetted it from stock 148main to 152main and slow jet 38 to 40. Since winter is coming it's going to run alittle lean but after the bike warms up it runs fine and in the summer time it will run fine I figure I don't ride much in the really cold weather. When it comes to buying jets if you really know what you need then you only need to buy maybe like 4 (two mains and to slow jets) I got my jets from jetsrus.com because i couldn't find the jets at local stealerships. Also jetsrus has allen head screws for your bowl under your carb. I was curious I didn't see a pilot screw on the 06 400ex when I had my 02 400ex it had a pilot screw. So I guess they did away with the pilot mixure screw on the new 400ex's meaning 05 and up. From all I read is that the header pipe was made good enough from honda and that just a slip on pipe is good enough if you are not planning on totally going all out modifying the engine.

 

so when u got those jets did they do anything to performnace or is it because u are above sealevel i dont really get those things. so u are sayin that the stock headers are good enough and just buy a slip on wat kind would u recomend for like 300 or less

 

ohh and the jets theres a lot of different sizes how would i pick from one or the other and would it do anything

 

i go ten at a time , if stock 148 id go 160 to start run wide open in third and then kill motor and pull clutch and stop! pull plug and if white go to 170 if black go 155

 

Well for jetting it depends on where you live and your altitude. The higher up in the U.S. you are the leaner you will be and the lower in the U.S. you are the richer you will be. So example would be someone in Montana would have a smaller main jet than someone in Louisiana. Because the person in Montana is a lot higher from sea level than the person in Louisiana. Actually the person in Louisiana could be under sea level. And it also depends on the time of year and weather to the jetting you need to use. In the winter you will run leaner and the summer you will run richer. It's really just trial and error with jetting. A good pipe at a good price is HMF and I like the white bros. R4. And if you really want to go cheap and loud you could get a DG. For Picking out what jets you need I highly recommend http://www.jetsrus.com/main_page.htm
they ship fast and you can get exactly what you need. To start with a pipe I would go from stock main 148 to 160 and see how that feels and put a slow from stock of 38 to 45. When you buy from jetsrus buy main 150-180 and slow 40-48. Since I don't know where you live and how cold or hot it is it's hard to tell you what to use. If you smell gas in the exhaust you are really rich. Or you could just buy the jet kit from jetsrus.

Try these websites out:
http://www.dgperf.com/store.asp

http://www.ehsracing.com

http://www.rockymountainatv.com

http://www.dunereview.com/AllVideos/

http://atv.off-road.com/atv/ar...eDetail.jsp?id=192286

http://www.angelfire.com/extre...hee/links/links1.html

http://www.denniskirk.com/jsp/common/Frontpage.jsp

https://hmfengineering.com/index.php...&searchby=pipe
http://www.haleyengineeredperformance.com/

http://www.jetsrus.com/main_page.htm

http://www.prm-atv.com/


Enjoy!

 

I found a good forum read this through it explains how to jet a carb pretty good.
http://forums.atvconnection.co...10/threadid/477290.cfm

 

well thanks alot those websights are veryhelpful i might actually buy one of those dg pipes ohh and for where i live i ligve in illinois and the weather changes but now its atleast highs about 40 to 50 in the summers its about 80 to 90 and the jets i apreciate the help on them i will buy them nce i get that exhaust and once again thank u

 

The DG RCM Slip-on is going to be very loud and to be honest with you, you might not see any real gains from it but loudness. You might get a little bottom end but that about all. Really check out HMF before you buy a pipe. They are cheap and from what I read very good. I settled for just a exhaust cap from EHS Racing the stock pipe sounds really good with just that cap on it. And I did really notice a lot from just a UNI filter and the exhaust spark arrestor cap from EHS. Ohh and the air filter box outwears EHS lid instead of just having an open lid. Again before you buy DG really think about HMF or White Bros., or Yoshimura.

 

ya i was looking at them and i was thinking they where a liitle to cheep to gain anything except some noise im looking at an hmf one and this one looks really nice and its got the jetting specs s i might go wit that one seems good for 270dollars and i might pick up one of the jet kits thay have well thanks for the heads up on the dg exhaust

 

If you remove the air box lid it will run lean and ruin your engine w/ out the proper jetting plus it will make the air filter 10x more dirty 10x faster! also w/ you remost the exhaust cap ( the spark arrestor and baffle ) it will take a litle bit but you will rune your valves because there is no back pressure! Just buy air box vents and but a new exhaust and if you cant like me just but a aftermarket tip off of ebay!