Exhaust for an 05 CRF250X

Does an exhaust for CRF250X make a huge difference? Which exhaust is a good one? Do the header pipe and muffler or just a slip on? What should I do to give it some more balls?

If you want more top end get an 04-05 R head pipe for it. They are cheap to buy used and will give you a little more topend.

Not a lot of difference at low rpm, but anything that allows increased flow will improve the mid-range hit and the top-end, IF you also open-up the airbox and jet richer on the main jet. You can get more flow by simply removing the quiet insert from the stock muffler, BUT be advised that it is LOUD that way. Many of the aftermarket slip-ons will do the same thing while making less noise and also weigh less--some of them weigh a lot less, just depends on what you want to spend. Consider that you will be sacrificing some durability if you ditch the stock stainless steel--titanium can be quite delicate in fact. If you change to a short-radius header, like for the R models, you will lose some of the low rpm torque in exchange for gains at higher rpm. I would say for racing on closed-courses the trade-offs are definitely worthwhile, but for trail-riding only I would keep it stealthy by just drilling out the diffuser in the stock quiet insert.

How do I drill out the diffuser? Where is it located? just drill a hole in it and leave it open? I dont mind it if its loud.

Do you lose ALOT of bottom end when you put the R header and pipe on? Still have to jet it?

How do I drill out the diffuser? Where is it located? just drill a hole in it and leave it open? I dont mind it if its loud.

Take out the quiet insert and on the back end it is just like a tube with a cap welded on to it---drill thru the cap a 3/8" hole and re-install into the muffler. If noise isn't a problem, just leave the quiet insert out--you'll need to go up on the main jet--how much depends on how much you open-up your airbox. Keep in mind that excess noise can create land-use issues with people that don't like motorcycles.

Do you lose ALOT of bottom end when you put the R header and pipe on? Still have to jet it?

It's enough to be noticeable--I would say it could be a factor if you ride a lot of tight technical trails, but it's easy enough to switch between the two if you can find an R header cheap.

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