Can you jet your bike using the stock muffler and filter? Will it do anything for ya?

 

Without modifying the intake or exhaust jetting will most likely make you run rich, unless you have a stock lean.

 

You don't rejet a carb unless it needs it. It makes no difference if its stock or modified. If you make a drastic change in climate, alltitude, etc... you'll probably need to recalibrate you carb. If it runs fine and your plug looks good (brownish) chances are that if you go in and start changing jets you'll lose perfomance and gain a headache.

If it ain't broke, Don't fix it.

 

Most manufacturers jet lean at the factory, to meet emissions standards. When you jet, you want to start out at a point that you know will be a little rich, then back it down until it just runs a little lean. Then go back one size larger to be sure you aren't lean.

 

Rejetted my Ozark with no aftermarket pipe and it runs a lot better now (modified air box).

Why do you guys say it won't help, when you buy a jet kit, it says on every package I seen: Stage 1, for use on stock or mildly tuned motors, with modified air box, stock or aftermarket exhaust.

I am gonna pipe my bike, its just on backorder, I couldn't wait so I went ahead and rejetted.

 

I wasn't aware that stock tended to be lean. Of course your Ozark ran better rejetted. You modified the intake to allow for more air.

 

If you have a Z400 for example...It is jetted so lean if you remove the air box lid with no other changes it will run like crap. You can gain a little pep just removing the lid and bumping up the main one size.