I am still getting familiar with my new 450r but I just rode my friends (same year and model, 2006) and mine seems to have more power, it is also louder. My exhaust has a larger hole and than his, and mine looks like it has no quite core or something. Is there any way to tell if i have an HRC kit?, i doubt it, (bought it used). Also i am missing a piece of what looks to be the airbox. It is on the left hand side under the seat and clamps on tho the airbox. I looked at my friends and his has like a minny airbox.

 

I got looking at it and the part that im missing attaches to the intake manifold, what does this do? this quad was used in the dunes so it had no air box lid, i got a new lid but i want to know if i need this other part cause i do a lot of muddy riding

 

The guy before you may have taken out the baffles and if there is about a half an airbox that is the hrc kit lid and it does come with a new endcap...so there is a possibility you have one and you will also have a different cdi box...I also believe there was some other change to the airbox and you should have a cam and larger jets then your friend about a 185 I believe...It is possible you have one and you should be able to beat your friend pretty badly...It also may not be and it sounds like it is louder because of the airbox being open and the baffle...Check to see if you have the cdi and jetting.

 

ya it didnt have an air box lid at all, dont think it has the hrc kit, will check the cdi tommorow. Its just weird the exhaust still looks like it has the tip and the insert its just a bigger hole. Stil wondering what that thingy is on the intake manifold and whether i need it or not. Thanks for the help!

 

If your quad is jetted for no lid, you will need to rejet when you put a lid on it or you will be running really rich.
I ride on the trails through mud and water and I have a cut open lid on mine and I have never had any problems.

 

ya its going to the dealer this week to change the jetting, which is why i want to know whether i need this box off the intake manifold cause it will also likely effect the fuel mixture