Help with exhaust.

[rid3r3d33]

Hi everyone. I have a few questions and this might make me sound retarted :) haha, i still need them answered. I am going to get a Slip-On Pipe and i can't jet it because my dad bought me my 400 and for some reason he's not going to let me. I need to know what will happen if my 400 runs lean? and what running lean is? thank you so much for your help and any other things i need to know, feel free to post. Thank you.

[AZ440ex]

Originally posted by rid3r3d33
Hi everyone. I have a few questions and this might make me sound retarted :) haha, i still need them answered. I am going to get a Slip-On Pipe and i can't jet it because my dad bought me my 400 and for some reason he's not going to let me. I need to know what will happen if my 400 runs lean? and what running lean is? thank you so much for your help and any other things i need to know, feel free to post. Thank you.

If it is too lean it will burn up the piston. Put a new plug it in when you do the exhaust and keep an eye on it. after some run time pull it and see what color the porcelin part is( by the electrode), should be a light brown. Black is too rich and white or grey is too lean.

[rid3r3d33]

Ok i understand now. What do i do if the 400 is running lean (porcelin is white)? If it is doing that then I might just get my dad to let me jet it. He says that i can't jet it b/c "if it is already running fine, why mess with the carb and risk screwing something up?" I have heard it is easy and that it is one of the easiest mods to put on. If it isn't running lean, nothing needs to be done, correct? Thanks for the help.

[drew416ex]

yes if its not lean then you are fine. The only thing is most of them are lean from the factory because of emissions laws but they arent lean enough to hurt the engine. When you add that exhaust it might pust it over that limit. And remember, just because something runs right, doesnt always mean it is jetted right.

[TRX_450]

granted im in a different state and elevation, im running an HMF slip-on and didnt rejet and it runs great, has for about a year and a half.

[Hondamaster5505]

jet it when your dads not home. he'll never know..;)

[rid3r3d33]

So are you saying that it might not be jetted right anyways? how would i know if thats the case? and i think i will have to end up trying to persuade my dad into letting me jet it.

and TRX_450: im guessing since your's runs great without rejetting maybe i won't have to and mine will run fine. hopefully thats the case.

Thanks for your help guys.

If anything else comes up on the topic, please be sure to tell me.

[drew416ex]

Originally posted by rid3r3d33
So are you saying that it might not be jetted right anyways? how would i know if thats the case? and i think i will have to end up trying to persuade my dad into letting me jet it.


Since its different everywhere you go, there is no way for the manufacturer to beable to jet it right everywhere. So they find a happy medium and thats where it is set, along with keping the EPA happy. So 99% of the time, it isnt jetted dead on. Not saying it wont run good, but it would most likely run better being jetted.

[rid3r3d33]

Ok i understand now. Haha and i would jet it when he's not home but i wouldn't know what i was doing :). and even if i did it would take forever. So if someone wants to give me step-by-step instructions (very detailed) i could probably do it. Thanks for the help.

[dariusld]

Running lean also causes it to run a little hotter, which is also bad. Its always better to be a little rich than a little lean.:)

[rid3r3d33]

Ok thanks for the help. Can someone give me step-by-step instructions on how to jet my 400? if so i would be very grateful. Thanks.

[honda729]

if you only need to change the main jet its easy, turn your gas off take the big bolt out of the bottom i cant remember the size, then take a 6mm(i think) socket and take the main jet out,it sits right behind the big bolt you cant miss it. you wont even need to take the carb off.
heres a form on how to change the pilot if you need to. the main jet is the tall one next to the pilot http://www.exriders.com/vbb/showthread.php?threadid=221742

[rid3r3d33]

Thanks honda729. I will do that soon. hopefully i don't mess anything up. it shouldn't be too hard.
Thanks for the help.

[honda729]

no prob shoot me a pm if you get stuck

[leasureryan]

tell your father that he shouldn't have allowed you to buy the pipe if he didn't know what all needed to be done. He should do his research, because spending a little money buying a pipe is cool, but not letting you jett it when it WILL NEED to be rejeted, could end up costing him alot more money in the long run. Jeting isn't just an option....it's a nessecity!!!