08 YZ450F exhaust, system vs slip on and who makes them.

So after looking at a bunch of website, DRD does not make a slip on pipe for 08 yz450f. I'm guessing it hast to do with the header pipe being too big.


FMF and Two brothers make a slip on but I'm worried it may not be the best option in performance and price.


I ride trail and desert. My concerns are getting better performance ( bogg ) and adding a spark arrester. I'd also like to keep the sound close to legal on the trails.



Is the drd SS/AL comp  7404 going to be best for me?


Bike is stock. after the pipe I will double check jetting. It's hard to research because the website don't have too much info. I'm not loaded with cash so I have to do my research before buying because I'll be stuck with what ever I get.  :)


(I have heard of the 06 CDI and other upgrades but I need to start with a pipe for the sparky.)

You can just put a Pro Moto billet end cap and spark arrestor on the back of your 08 pipe.

If you really want to get rid of the bog send your carb to Zipty racing and get all the mods. You'll still have some coin in your pocket book.

Edited by stevethe

Well, you're right about the carb, to a point, but the '08 exhaust has to go.  Same with an '09.  The shorty muffler cuts up to 7 hp from the mid range on the bike compared to a simple slip-on, and more improvement is possible with a full system because the OEM header is too large in diameter as a compensation for the restrictive exhaust.  Even with one of the internal baffling cones removed, the muffler is still ridiculously restrictive, and apart from how cute it is, it has no redeeming merits whatsoever.

Once you knock out all the baffles on the 08-09 that make them restrictive it is pretty much a fmf straight through system without the mega bombie thing in the head pipe.

I should mention it's not real easy to knock out the front baffle but it can be done.

Edited by stevethe

With both baffles cut through, it's also rather ridiculously loud.  The thing was junk the day it was bolted on the bike, and should simply be scrapped.

It is really just a little louder than a fmf system due to the bombs that quite the fmf pipes a bit. However the pro Moto billet end cap has a baffle that can be left stock or shortened for more noise.

I ran a 08 YZ450 header and muffler on my supermoto on the street. I ended up cutting the rear pro Moto billet baffle in about half. Now I run the same header with a fmf ti muffler on the rear mostly for the weight difference. The 08 YZ muffler mid pipe assy. is quite heavy in comparison.

Edited by stevethe

I can't speak for hp gains but the Lexx Mxe with a quiet core spark arrestor and can be opened up with the race tip that is quite a bit louder. I put the race tip on once and decided to stick with the quiet core... It seemed to have plenty of pep and wasn't annoying...

Plus they are $199 on Rocky Mountain atv and I think they can be found on eBay in the 170's shipped

Got the DRD full system for $339 when RMATV had the $50 off sale.


Made a big difference but the bog was still there when you snapped the throttle open fast even with correct jetting/fuel screw settings.


Retiming the accelerator pump and doing the wire tie/oring mod made all the difference.


It almost feel as responsive as fuel injection now.


The retiming/wire tie mod is free. I would start there

Edited by UncleLuke

Some buddies from work are trying to get me to ride at that Virginia City race. I need a spark arrester and I don't want to waste $100.00 on an end cap. I don't really need more power but eliminating bog would be nice for floating the front over trees and rocks or blasting threw water. 


I found the drd for $351.00 part # 7404.( i think it was.) So far its the best price. I'm just not sure if that pipe will be legal for sound and I don't recall seeing a sound rating.

FMF has slip on's for $100-$120 less than the drd full kit, but I'm not sure if it is a good deal. Because of the size of my head pipe, a full kit seams like the most improvement.


I'v seen Big Gun, Two brothers, Leo Vince, Lexx, Yoshi, Ark(something). They were all more $ or too flashy. ( red or gold.)


Am I missing any brands or deals?


Anyhow back to the garage sale adds for me. 

Get the full DRD system and don't look back. The best bang for the buck performance wise and much quieter than a slip on.


And time the accelerator pump to get rid of the bog

The DRD is an excellent value, and pump timing is worth a look.  Refer to the manual.

Rode some trails with DRD and o ring mod. Carb is still stock. A pop or two when kicking the bike over. I have a hard time because I'm shorter and can't reach, ( so my kicks are light.) Starts good with a normal kick.

Maybe slight decel poping. Bog is gone. I'm sure it could be jetted a little better for a guy who is racing but for me it's good. I do want to ditch the o ring and get it jetted to eliminate bog. I need to check the plug to see if its running hot. Header blued pretty good right away. Maybe running lean? I use more of the lower section of the throttle than the upper half. (I'm slow). 

"Some" decel backfire some of the time is in fact a sign that the pilot circuit is jetted about right.  Too rich, and you'd have trouble with throttle chop stalling and a "grumpy" engine at low speeds.


The exhaust is just going to be hot and that's that.  When I had a Ti4 on my '03, it used to turn blue clear to the muffler during a ride day.  Normal.  Sounds to me like it's about right. 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now