XR 250 Aftermarket Exhaust

I have a stock 03 XR 250, and I was wondering if it is worth it to replace the exhaust. Would I get better response with a new exhaust than to replace the baffle? If I do get a new exhaust system, should I just get a slip on or new headers too?

Also, I have heard something about removing the air box cover? Did I hear right? Is this just the cover underneath the seat? Can't water get in if you take this off?

Lastly, should I rejet if I get new exhaust?


Putting a new exhaust wont give it Overly much more power, But it will make it LOUD!!!!! And sometime's thats not worth it, for just a slight more power.

Personaly I would recomend just keeping the standerd muffler, and either modifying the baffel, making a new one or buying an aftermarket baffel. Or just removing the baffel all together!

And then take your header pipes off, and grind the welds off the inside of the pipes, where it meets with the head.

Yea about the air box, you just yake that snorkle thing out. just tke the seat off and pull out that plastic thing! Naa, you'll be rite, water wont get in there! Dont see how the snorkle thing would of stopped that in the first place.

So to answer your question, you could spend a Heap of money on a new exhaust system, and question yourself if you can tell the difference through the noise, or you could do what everyone says on here, and be happy with the FREE power gain! :cry:

I had a 2000 XR250 with a FMF powercore 4 Q, and now I have a stock 2002 XR250. I didn't do any of the free mods except remove the baffle on my current bike, and I can tell you, I had way more throttle response and power with the powercore pipe on my old bike. if you do the free mods, and get a power increase that is noticable, than i wouldn't get a pipe. look into a big bore kit before a pipe if you really want power.

I own a 2004 XR250 and after taking out the baffle and removing the snorkle I noticed a huge difference in ability to climb long hills where i bogged down and died before. The throttle response also seemed much quicker. I'm not sure which was more important since I did them together.

Then I ground down the header welds and frankly could not tell any difference before and after.

Later, I added a White Bros. E2 exhaust (it was a gift b/c by then I was happy and wouldn't have gotten it on my own), and I did not really see much if any difference, when using the quieter insert, with the stock (modified) bike. It was definitely stronger at low and mid rpm's with the "competition" insert but way too loud for me, and I'm sure, my friendly forest ranger.

2004 XR 250

2004 CRF 250 X

2003 CRF 230

Find the post about modifying exhaust baffles. With the baffle out, air box modified, and carb rejetted you will notice a large difference in power and response but it will also be much louder and low end will suffer slightly. Modifying the baffle is a happy medium that does not sacrifice low end grunt. I'm a firm believer that the only thing you will gain by replacing your exhaust is a weight savings of about 2 lbs. I'd go on a diet for a day before spending $300.00.

Alright, I went ahead and drilled 3 holes in my baffle. I haven't been riding yet, but I can notice the noise. I also ordered a UNI filter, would it be necessary for me to take off the snorkel still with this filter? Should I put some UNI filter foam where the snorkel out to keep it clean if I do? One more question, what should I rejet it to with the UNI filter, 3 holes in my exhaust, and possibly the snorkel removed?

A word of advice about the use of a Uni Filter.

They are a very good improvement over that of a standard air filter, however you need to familiarise yourself with the correct procedure for cleaning it regularly.

It needs to be cleaned with turps, then with a mild soapy water solution, then leave it to totally dry, and when re-oiling the foam, the idea is to only use very little, and cover the entire area, or if you use too much, you will end up choking the foam, and consequently reducing performance.


I've actually had very good luck with the spray Uni cleaner and spray Uni oil set. Very easy and not too messy.

Question, are those of you using Uni filters using rim grease? I have been using it just out of habit.

The problem with using anything other than dedicated foam oil, is that it may have given time, a reaction to the foam, and eventually deteriorate and cause minute particles of foam to be sucked into your carby....

As well as that, any other oils may not have the correct consistency to stick to the foam, and which will allow the oil that you use to also find its way to the carby.

I know it’s probably over the top, but I thought it was worth mentioning.

I haven't had a great deal of experience in using foam filters on bikes, but I have in 4x4 racing, so I suppose the same applies.

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