Oil change and plug change and k n air filter. Now bike backfires
 

Hi I replaced my oil and plugs on my hawk. Also installed an k&n air filter. Bike starts fine but now backfires when I give it throttle after it warms up. Can someone please help me I would appreciate it. Thanks.

Take out the K&N and put a stock filter back in.

If you want to use a K&N you have to rejet the carbs.

Yes.

+1

Most likely it's the K&N, but you didn't mention what kind of plugs you installed. If you installed the recommended NGK iridium or platinum plugs, gapped correctly, no problem. But if you installed Splitfire or E3 or some crap like that, they can make many cars, trucks and motorcycles run like s#@*.

Another +1. You'll find many folks are sticking with the stock A/F.

backfiring usually means lean which is what a K&N will do since it flows better. Get a FactoryPro 1.1 kit if you want an easy way to fix it while using the K&N. Also DePAIR.

Shimming the carb needles seems to work quite well on my '02 with a K&N filter - I put a #4 brass washer from the hardware store under each and no backfires or lean mixture. Others have done this so search for more info.

And I see that was your first post! :) Welcome to the forum, Sherm831!!! Utilize the search function and you'll usually find that at least one other person has had the same problem you're trying to remedy. If you can't find the answer in a previous thread, then ask the question. There are a lot of folks who have a wealth of working knowledge on these great bikes and they are always willing to share.

The K&N leans the bike out, a lot!;)