400EX Jetting question..

[Racing Rice]

I have a question for all of you..

I have a friend that is putting a 160 Jet in a stock bike. Even stock air filter I believe, not to mention, the quad is a little abused anyway. This seems like a little over kill to me although I dont know to much about Jetting.. Or 400EX's for that matter.

What are your thoughts? Is this a bad idea or will it be ok until he can get some other mods like an Air filter and exhaust..

I really dont want to see him kill his quad because he's a moron.. No honda deserves that..;)

[Atomic83]

A 160 on a stock bike will make it run like crap, unless he takes his airbox lid off or something, but that will still be to rich.

[Racing Rice]

Thanks... thats what I was kinda figuring. But hes one of these people that will argue until your blue in the face...

Hes said he rode another stock 400EX with the same Jetting and it ran great, which is REALLY hard for me to believe. I dont know if the person he was talking to was full of crap to or what, but it didnt make any sense to me at all.

[BornOnFire]

So, what other jet do you recommend? 165?

:devil

[Racing Rice]

Originally posted by BornOnFire
So, what other jet do you recommend? 165?

:devil

Well, I personally wouldnt mess with the jetting on a stock bike until you have some other mods to put on it as well.. But thats my thinking anyway.

[Atomic83]

yeah, don't rejet until you do some mods.

IF it ain't broke don't fix it..:blah

[Wheelie]

A 160 main jet is too to much for a stock 400 to handle, let alone one with a pipe and filter.

[BornOnFire]

So................what are YOU recommending??

155, 160,.....................???

[BornOnFire]

The reason I am asking is that I am about to do the re-jet myself and I am also installing the WB E-Series slip-on exhaust at the same time (as soon as it arrives from Marcum next week).

I think that Terry Marcum sold me the 165 jet based on the new pipe and the current mods I have(K&N, Modified airbox, 14 Tooth sprocket). Do you guys think that this may be too much? I have little or no experience with this $hit and I do not want to screw the bike up!!

Thanks....

[Atomic83]

I think the 165 will be rich unless you take the airbox lid completly off, but you'll just have to try it out and see how it runs. Thats the only way to tell for sure.

[Wheelie]

I recommend a 155mj, your choice of a #40 pilot is spot on.

When Dirt Wheels did the 400ex pipe review a while back, they were running a 155mj with all but one pipe, that one was a CT Racing pipe.

If the top gears feel 'flat', and low gears pull o.k. you're running too rich.