[Kingrah]

Wasup everyone. I’m new to the forum. I Just bought a 07 CRF450r. The bike needs a new header. I also want to change the muffler while I’m at it. I plan to purchase the TX Restyle kit but I don’t like the way it looks with the 07 pipe. Therefore I want to know, can we put newer model mufflers(slip ons) on our bike with the 07 header? The newer mufflers are a bit small. But I’m just curious to see if any newer year pipes are interchangeable because they tend to come smaller. Thanks in advance for any help.

[JimDirt]

Welcome to the site !!

Unfortunately , the dual setups will not fit due to subframe differences ,as well as the number plates do not stick out far enough on the left side to accomodate a muffler

Could you mock something up to work .... its possible , but for what gain ?? , it will not improve the power , it will not save weight , it will add it (about 4 lbs) , and there is basically nothing to gain by trying to attempt to make this work , unless you have lots of time on your hands , welding experience with Aluminum as well as Stainless , and tube bending machines and lots of time ..... did I mention you will need lots of time ??

You will be better off living with what you have or finding another aftermarket setup ( single) that will give you some of what you are looking for ( basically a shorter muffler) , you could cut the muffler down a bit , but the shorter the muffler the louder it will be ..... The entire reason for dual mufflers was mass centralization , it had nothing to do with performance , the reason there are 2 is because with one that short it will be really loud , as well as all bottom end and no top end power , so the 2 give it the flow needed ,even though the holes are half the size , and somewhat keeping the noise to a minimum .... I just bought a 2020 450R last week , and let me tell you , it is LOUD ...

[Kingrah]

Hey Jim,

Thanks for the reply. But I’m not interested in the dual pipes at all. Lol. I just wanted to Know if it mattered or is it a big difference between the 07/08 muffler pipes versus the other years. Where as though if I put a 2010 muffler on my bike with the 07/08 header, will it cause any damage?

[JimDirt]

Oh .... Well when you said "newer" I was assuming Duals ....... anyway , the frame differences to me would be significant enough ( subframes mainly) that mounting would be a issue ,and usually the shorter mufflers are with the duals ...... of the "older" models from 02-04 they were the longest , the 05 on , were 4 inches shorter , then the duals were even shorter , like my 2020 , the mufflers are fairly short , but the openings are smaller in diameter than the older ones (02-08) to keep the backpressure up ,as 2 large openings would kill the bottom end power ......... but basically ,05-08 would pretty much be it as far as some kind of fitment without compromising power delivery , as the 2 mufflers do not give any power advantage , just center mass distribution , and shorter mufflers have smaller exit holes , so that would affect power delivery .... and another thing that is something to consider, shorter mufflers will alter center of mass even though only slightly , it will affect handling to some degree because of where the weight gets moved to , so you could even need to change a spring rate by running shorter mufflers .... if you are just play riding , then no issue , but if you start jumping , then that opens up a whole different scenario ...