hmf or not

[w.va rider]

I am not sure if i should put an exhaust on my new kfx450 because in the past 2 bikes i had, i put exhaust systems on them and had valve problems or had to rebuild them. Has anyone had any trouble with a slip on HMF Sport Series exhaust? I am talking about internal motor problems or anything in general because of an exhaust on a kfx450r.

[Pappy]

An exhaust system should have zero effect on engine wear or issues......UNLESS.....

You are failing to properly rejet for the exhaust. With the KFX, you will be buying a fuel managment/efi controller along with an exhaust.

[w.va rider]

Well I called HMF and they said as long as i dont change the air filter and keep the air box lid on i dont need to buy a power commander or anything like that. Basically leave the intake stock. I was just wondering if anyone has had problems with the KFX after installing a slip-on. But thanks Pappy.

[MtnEX]

Here is my opinion.

I think a slip on for the KFX is a waste of money.

1 - this is a performance machine, not a 250ex.

2- Titanium head pipes are prone to cracking. Buy a slip on and you'll be buying a new head pipe down the road (not cheap) or a full exhaust.


Buy the Jardine RT99 stainless/aluminum full system for the KFX.

You can get it through kb motorsports right now for not much more than a slip-on... which is a great price considering this is a $610 race system.