Now What? -Jeting? Scoops? Cam? Revbox?

[SandShark400]

I was wondering if I should buy a jeting kit or a high performance cam or even just a revbox. Is it hard to start it with a revbox? Point me in the right direction and if i do nuy a jet kit how do i "JET"?

[bwamos]

Well if you have a pipe and filter, you HAVE to rejet anyway. You'll be running way too lean and can burn up your rings/valves, even crack you exhaust, or warp your cylinder.

Here's a great article, that will give you an idea into what jetting is. http://www.duncanracing.com/techfaq/Tech_keihin-carburetion-jetting.phtml

If you go with a jetting kit, it gives you instructions on what to do. BUt they usually only allow to setup for an aftermarket pipe and filter. High compression pistons and Cams, etc.. aren't included in their jetting instructions.

If you get a cam later, you will need to rejet again. Anytime you change anything on the motor you need to check the jetting.

Jetting isn't that hard to do physically. The hardest part is learning the motor, to know when the jetting is correct, and when it's rich/lean.

[RiderTRX400ex]

the only time you should have problems with a revbox are if you live in really cold temps, but other than that you should be fine.. IMO rev boxes are kinda a waste, unless you have a cam that loves to rev

[bada440ex]

white bros rev box helps

[wolffie]

www.jetsrus.com has awesome prices on jet kits and individual parts. heres a pic of the 400ex carb once you have removed the floatbowl:

[jordan_m6]

my 400 starts right up with my hot shot cdi, but i put in a cam and it removes the decompression valve and that makes it hard to start.

[400exstud]

that doesn't look like a 400ex carb unless the accelerater pump is gone.

rev boxes only add 1000 rpm. that sounds good, but where would that rpm come at. it comes once you are at the maximum rpm, or full throttle in any gear...how often do you stay full throttle in any gear, not often or long.

don't waste cash on a rev box, if you do, you better have a few extra batteries on hand

[rooster_20]

I was bout to say that doesnt look like my carb??

[wolffie]

its off my buddy's 05 ex:confused: perhaps the 05's have different carbs?

basicly the same thing. 4stroke carb is a 4 stroke carb, 2 stroke carb is a 2 stroke carb.