Exhaust choice and proper jetting

[Ramm-jett]

Hey every one

New here and I just bought a new 2007 TRX400EX7.I want to put an after market exhaust on my bike and want the best value for my money.I wanted to put a full Yoshi,but for the money and the amount I am going to use it I was thinking of the HMF slip-on.I 've read good reviews on that pipe and it seems to be a decent price.What about jetting the bike?Do I have to buy a complete jet kit or will the pipe makers supply one when I buy the pipe.I just want to be extra careful as I have heard of guys blowing their engines after putting a pipe on.Also does any one know why the 2007's are called ex7's?or are there 2 different models.
Thanks<:devil:

[RaginRedneck]

Hi,
Welcome to the board. For the exhaust check out these threads:

1) Different clips of what different exhausts sound like:

http://www.exriders.com/vbb/showthread.php?s=&threadid=346007&highlight=exhaust+clip

-Also some good general discussion about likes and dislikes of different exhaust systems

2) For jetting a bunch of us listed which mods we had, where we were located at (temperature and altitude)

http://www.exriders.com/vbb/showthread.php?s=&threadid=344906&highlight=jetting

These should get you a good starting point, but the best test is to jet it and then do a plug check.

I haven't heard of a company sending jets with an exhaust, but I'm not sure. You can go to a local dealer once you think you have an idea on what you should be jetted at and get a handful of jets fairly cheap; i.e. you think you'll need a 155 main, so go buy a 152, 155, and a 158.

Good luck!!!

[Ramm-jett]

Hey Thanks

I checked out that thread for pipes(awesome!)Too bad there isn't a two brothers clip though I was considering that pipe as well.

[RaginRedneck]

Search You tube for two brothers, or on that exhaust thread ask if anyone has a clip if you haven't already. You never know.


Glad that info was helpful.

BTW when it comes to buying individual jets or a kit, I would recommend a kit, IF you are going to be constantly adding things to the quad, that way you have options.

I bought a jet kit for mine (Mains only), but that is because it came with a new CDI box, so it worked out well.

-RR-

[elmer91]

HMF is pretty good. i just bought one, and got it today. looks great. i know with some exhuasts, HMF will send jets, but not with the one i just got. we put a HMF onto a rhino, and it came with the jets. but the best thing to do with finding the right jetting is to just try a few different jets.

[Ramm-jett]

Thanks for the input,

I'm still quite new on the issue,but how will I know what is the right one?Do these things run too lean or somethin when a lower restriction pipe is put on?:huh

[2001400ex]

I have a slightly used HMF slip-on powdercoated Gunmetal/Gray that I will sell you for considerably cheaper than on HMF's website.

Let me know if you're interested and want to see some pictures.

By the way I am a full blown HMF fan I will never run any other exhaust on any of my machines.

[Hondamaster5505]

Originally posted by Ramm-jett
Thanks for the input,

I'm still quite new on the issue,but how will I know what is the right one?Do these things run too lean or somethin when a lower restriction pipe is put on?:huh

More airflow = Leaner

Less airflow = richer

400EX's are generally jetted fairly low from the factory. This is because of emissions and it makes them run fairly lean. By adding an aftermarket exhaust, you are getting more airflow thus resulting in even leaner conditions.

You will know your lean if:
-Pops a lot on deceleration.
-Spark Plug is sheer white.
-Engine runs hotter.
-Engine acts funny on acceleration.

To know if you are jetted properly, the spark plug will be a tan color. It shouldn't pop alot on deceleration either. If you are too rich, the plug will be blackish and it will bog a lot.

For the HMF slip-on exhaust, I would start with a Kehin #155 main with a #42 pilot jet. Then ride it and check the plug or for symptoms. You may have to go a little up, or a little down.

[Ramm-jett]

thanks Bro

Finally clarification,that was some awesome info dude!Way more clear now.should be ready to ripp soon with that new pipe.

[Ramm-jett]

Hey 2001400ex

I'm definately interested in that slip-on.Does it look good enough for a brand new bike?If so let me know,send me some pics and a price and I will let you know.

[Hondamaster5505]

Originally posted by Ramm-jett
thanks Bro

Finally clarification,that was some awesome info dude!Way more clear now.should be ready to ripp soon with that new pipe.

No problem:)

[2001400ex]

Originally posted by Ramm-jett
Hey 2001400ex

I'm definately interested in that slip-on.Does it look good enough for a brand new bike?If so let me know,send me some pics and a price and I will let you know.

I would put it on a brand new bike, and my toys are something I am VERY anal with. I will send you some pictures if you send me a PM, and make up your mind if you want to or not. Sound good?

[YELLOW_TRX400EX]

if he dont whatn it let me know im interested on that exhaust...

[07trx400ex]

I had a very hard time getting my jetting correct, and it is still rich to a minimal extent.

Take your time doing this because rich jetting robs hp at tq.

Be careful because it will act like it is hitting the rev limiter when it is rich.

Yoshimura sent jets with my RS-3 full exhaust and they were too big even with opening up the airbox.

[red_rider_069]

heres my yoshi carbon.. totally rips.. got from gopartsdirect.com.. gotta call them tho not available online.. great pirces

http://i281.photobucket.com/albums/kk220/red_rider_069/maride.jpg

[400ex28]

I would start at a 155 main and go from there.