Will it be noticeable?

[pastfast125]

I'm gutting my stock silencer..doing the whole silencer packing deal all that..and I'm gonna run no airbox lid, and re jet..will I notice a big difference with this? Are there any other basically free mods that I'm not thinkin of?

[440_Turtle]

you will get s little difference mainly from the jetting though. Make sure that you check your plug color to check for proper jetting.

[nakomis0]

Don't gut your silencer. Your just gonna make it alot louder and get very minimal gains if any. You'll probably lose some low end and gain a little in the top.

Remove your airbox lid, re jet if it needs it. Then maybe save for a slip on

[pastfast125]

how do you figure I'll get no gains, I've already talked to alot of people..doing the silencer prperly is basically the same thing as a slip on...and everybody that I've talked to thats done it has noticed good gains on the bottem, they just lost a little on top.

[nakomis0]

I said minimal gains. I'm against loud exhaust.

[440_Turtle]

Originally posted by pastfast125
how do you figure I'll get no gains, I've already talked to alot of people..doing the silencer prperly is basically the same thing as a slip on...and everybody that I've talked to thats done it has noticed good gains on the bottem, they just lost a little on top.

I dont see how loosing back pressure will give you more low-end power, you are actually going to loose low end power with the loss of backpressureand gain up top since it will be better flowing at the higher RPM's. Very similar to an H-Pipe for cars

[pastfast125]

oh, well my exhaust is already loud, and I dont ride trails, I just ride at NJORVP, where every quad there is already extremely loud.

[davidds]

Originally posted by 440_Turtle
I dont see how loosing back pressure will give you more low-end power, you are actually going to loose low end power with the loss of backpressureand gain up top since it will be better flowing at the higher RPM's. Very similar to an H-Pipe for cars

I totally agree, thank you.

[pastfast125]

welp, I dunno what to tell you, but everybody I've talked to that's done this got more bottem end. Anyway...Do you guys have any idea of a starting point for me on the jetting? no airbox lid and the silencer mod? Could I just get like an FMF power up jet kit? Thanks.

[YFZ450Ridr]

Originally posted by pastfast125
welp, I dunno what to tell you, but everybody I've talked to that's done this got more bottem end. Anyway...Do you guys have any idea of a starting point for me on the jetting? no airbox lid and the silencer mod? Could I just get like an FMF power up jet kit? Thanks.

right now i have a uni filter, with an outerwears, and no air box lid and i run a 175 main jet with the stock pipe and the slip on i have. i change the 2 pipes when i ride at different places for noise issues.

youll see a big difference in bottom end if you run a setup close to that. my dad has a z400 and its completly stock and the power between mine and his is so much different, even with the stock pipe on mine, much more bottom end grunt.

[pastfast125]

cool thanks man, I guess I'll try a 175 and see if that gets me in the ball park.;)

[wolffie]

pastfast125, www.jetsrus.com is the best place that i know of that sells jet kits! you can buy any size, in any quantity and it is cheaper than buying an FMF or K@N off of rockymountain!!!!

[pastfast125]

Oh sweet, thanks dude...I guess I'm set, I just gotta finish up my silencer.

[pastfast125]

what kinda carb is on the z400??

[pastfast125]

hmm, I dunno what to get....that jetsRus plaec has a jet kit for the z400, it has from 135 to like 165..and it says its for no airbox lid, exhaust, or silencer, stuff like that, but somebody that psoted in here said he's running 175, so I dunno if 165 will be high enough??

[pastfast125]

he jet kit comes with all the following brand new parts: Genuine Mikuni precision machined main jets: 137.5, 140, 142.5, 145, 147.5, 150, 155, 160, 165 and 4 stainless steel allen head bolts for the carb bowl. Instructions on jetting included.

This kit is for modifications such as the following: aftermarket air filter, air box lid removed, modified air box, aftermarket slip-on exhaust or completely modified exhaust or cams.