What if someone forget's to rejet

[sparta4188]

My friend is getting a kn air filter and a full exhaust system, he says this rejeting stuff is weird and he dosent want to do it, what willd it hurt? will he be to rich or lean? he has a 02' 400ex

[honda300EXtreme]

He will be way to lean, and if the problem is left alone long enough he could possibly burn up a valve, and tell him that jetting is very simple,

[sparta4188]

how long would that be?

[honda300EXtreme]

its hard to judge, just tell your buddy to jet the bike while hes adding the pipe and filter, he only has to increase the main jet, which is so easy, it not worth it to not do it

[400eXr1d3rZ]

Originally posted by sparta4188
how long would that be?

It's VERY easy to do, try a 158 main and 42 pilot, 2 3/4 turns out fuel screw from lightly seated. Take the carb apart once and you'll NEVER forget it.

[kcliff]

i just did my quad and it is easy. just remember the screws could strip, (my hose clamp from carb to engine did) When doing the bowl take it easy and becareful not to strip those either, once you have the bowl off it is so easy. I went ahead and replaced all 4 screws on my carb bowl incase i had to rejet, but I didnt I got the right main. and replace the pilot to a 42 i did and it starts so much easier and it idles like a champ now

[Honda#4]

You will be very lean if you don't rejet, jetting is simple. Try a 42 pilot 160 main 3 turns out on the fuel screw and put the needle in the 4 slot from the top.

[fastyz85]

sorry to steal your thread but what happens when you have a burnt valve and how can you tell?

[Honda#4]

It will start smoking badly.

[honda300EXtreme]

yea it will smoke and eventuall you will get a build up of carbon on the valves, which will kill performance, and running lean will make your quad run way to hot, so ask your buddy if all this is worth a 5 dollar jet and a few minutes ;)

[Unverfehrt400ex]

If he's not gona rejet theres not much point of getting the pipe and filter because with it not being jetted right he wont see near the power increase that he will if he jets it right