jetting questions

[slowleak]

ok bought a brand new 07 yesterday, and i wanna put my yoshimure full exhaust from my 01 on it. is it absolutely necessary to re-jet for the new exhaust or am i safe to ride it like it is for now?

also, it would be great if we had a sticky on jetting. saw all the ones about adding the 450 carb, but nothing about jetting for other mods. thanks in advance for the help!

[exrider12]

yes you will definetly need to rejet, the pipe moves alot more air so in turn you will be very lean

[hornetgod13]

Yes, you need to rejet for a full exhaust. Go ahead and put spend $20-30 more dollars and install a UNI filter.

Stock: 38K Pilot, 148K Main Jet and, Needle (non-adjustable)

Suggestion (with air box lid on): 40K, 152K or 155K, and buy an adjustable needle and put the clip on the 4th slot down if the mid-throttle feels flat.

There are literally 100's of jetting threads in this forum alone. A jetting sticky has been suggested but the moderators just won't do it. Not sure why. A jetting thread would be a FANTASTIC idea.

[slowleak]

yeah i hear ya on the 100's of jetting threads. it would be great if someone compiled a list of jet sizes all into one and stickied it.

anyway, i got the pipe on and tomorrow im going to pick up a jet kit. anybody else got amything to add? i forgot to mention i am below sea level if that makes any difference, and im running k&n with no lid.

I tried to make the sticky or something happen so add more and maybe it will work. Its a good reference because a lot posted their mods and elevations and jetting specs.

http://www.exriders.com/vbb/showthread.php?s=&threadid=344906&highlight=400ex+jetting

[kilgoja]

I just wonder why everyone suggests to change your jetting for summer and winter....I mean you don't have to do that with the stock setup...it works no matter what the temp and such....so what makes it different for an aftermarket pipe?...shouldn't there be one setup that would work year round?...this is one thing that has always confused me