After market airfilter

Posts: 62

Will I feel any difference in performance by changing the stock airfilter on a sand spider to a K&N or Unifilter? I have heard that it can increase power 10-15%. I find that hard to believe, but I am willing to try. The stock filter is not all that crappy and does not appear that it would restrict the air flow that much. To improve the flow would'ent it let in more dirt? If anyone has done the exchange, please let me know what you think.
Thanks,
Clint
And, would increased flow help my problem with the backfire? ( see my unanswered post in Maintenence and Repairs. Please)

Posts: 206

Whether or not you'll see improved power depends on how restrictive your intake is now. Some stock air filters (like on my Honda 400ex) have a perforated metal baffle on the inside that restricts flow. In that case, just an aftermarket filter makes a difference. It's something you'll have to look at and decide for yourself if it's worth it. Is the backfiring during deceleration? If so, that usually indicates a lean idle circuit. Increasing airflow will probably make it worse. You can fix that by richening the idle circuit. I don't know anything about the specifics of your carb, so maybe someone else can chime in, but your carb should have a pilot jet (or two?) that controls that portion of the mixture. Go up a couple sizes and see if it helps. It should also make starting the engine on a cold day a little easier. If you increase the flow of air, you'll also want to go up a size or two on the main jet(s). Any time you increase the amount of air going through your engine, you have to increase the amount of fuel proportionally.