I have a 2002 Scrambler 400 2X4 and bought a K&N filter for it. Some of my friends told me that if I put this on my quad I will need to jet the carb as well. Is this true? I bought the filter at the place I purchased my quad at and they didn't say anything like that to me. Seems if it were true they would have told me so so that they could make extra $$ jetting it. Any one know FOR SURE? Another person I asked about it said it depends on the altitude of where you live????? I live (and ride) in Florida if that does make a difference. Thanks for any and all help!

 

If all you bought was the K&N, and you still have the stock exhaust, then chances are you will be fine without jetting. Rejetting is necessary when you change the airflow significantly by opening up the intake and exhaust. If you still have the stock exhaust, just the addition of the K&N will not likely open the system up enough to need jetting. If you notice the engine popping at higher RPMs then you may be lean and need a bigger jet, but I doubt it would. [img]i/expressions/face-icon-small-smile.gif[/img]

 

Thanks for the FAST reply! Everything is stock on the scrambler. So are you saying that as long as I don't hear this "popping" noise I am ok and if I do I should replace the K&N with my stock filter? Or are there any other dangers that could possibly happen by doing this? Thanks again!!

 

Uhh, lets see....You should be totally fine with using your new K&N filter. If you put it in and notice that the machine starts "popping" or cutting out at higher RPMs, then this is a sign that you are running lean, aka too much air, not enough fuel. Hence the need to rejet to a bigger jet, to get more fuel in. If you were to experience this, then you could do a couple things:

1. Put your stock air filter back on and see if it still does it;
2. Pretty sure you can take your bike for a quick spin, ride it fast and get it revved way up, and then cut the ignition without letting off the throttle, then take out the spark plug, and if its white, then you know you are running lean.

But again I really doubt that you will have any problems. [img]i/expressions/face-icon-small-smile.gif[/img]

 

Thanks again 2min!!! You are too kind!! [img]i/expressions/face-icon-small-smile.gif[/img] I'm off to put her in!

 

I also wouldn't think that you would have to re-jet. It should be just fine. The scramblers have been coming with a 240 main jet since '01. The stock jet used to be a 230.

 

If you are not sure just check the color of your plug after a short ride. Should be a nice tan color.