ti 4 sl or factory 4 exhaust 4 an 03 450

What exhaust would be better for an 03 yz 450 the ti 4 sl or factory 4 exhaust?, the riding that I do is racing motocross and supercross and noise dosn't matter and whats up with twobrothers racing is that any good?. :cry:


I read that the White Brother E-series pipe works great w/ the YZ450f. Its suposed to really smooth out the power.

The Ti4 and Factory 4 are virtually identical to the best of my knowledge. The Ti 4 works very well with the Power Bomb header. The stock '03 has a "sag" or "soft" spot in the power curve at about 8000 rpm that shows up on the dyno. The surge of power that occurs as the engine pulls past this point is misinterpreted as a "hit" by many people. With this complete exhaust system in place, that "sag/hit" thing is totally gone. The engine pulls as hard at low speed as with the stock system, but from a little lower rpm. It pulls harder through the middle, and runs right up close to the rev limit before it drops off. Dyno runs I've seen show a wider, slightly flatter curve with just over 1 HP gained over stock. I like it a lot. :cry:

But, there might be something marginally better. :cry:

I havent herd anything about leoVince exhaust so I wouldnt buy them but what about two brothers are they any good ? and white brothers is two expensive

I havent herd anything about leoVince exhaust so I wouldnt buy them but what about two brothers are they any good ? and white brothers is two expensive

From the gist of your post, you haven't heard about any of them or you wouldn't be asking.

All the power of the system comes from the header. If you just put on the muffler you probably wont notice much. The header seems to add punch and the muffler smoothens it out.

As for the Ti4 vs F4, they are the same system. One is just prettier and comes with a useless jet kit that FMF couldnt sell before the system. The Ti4 slip on is just the muffler and mid pipe of the F4.

Keith...i thin your talking about the White Brothers Carbon Pro being extremely expensive. Take a look into the W.B. E-Series Muffler.

well I have herd about a lot of exhaust but I dont like white brothers or leoVenci but I havent herd about two brothers and I was confused about the Ti4 or the factory four :cry:

bryan all of white brothers is two expensive and y would you get the e-series for racing ?

factory 4 system...the ti 4 slip on, has no headpipe or powerbomb...the factory 4 is loud, ands more low end and you can tell you have it on..youll notice a big difference.

go to http://www.dirtrider.com

they have a shoot out test on all the exhausts for a '03 yz450f.

best pipes were Yoshimura, gytr and jardine.

I aggree that just getting a muffler is senseless.

you will not really feel the difference since the stock exhaust is actually pretty good.

If you cannot afford a full system right now, safe up more money and just right harder. A couple of teeth on the rear will feel like you just gained five horsepower or just get vp ultimate four fuel. 6% more horsepower just for pouring it in the tank, but you will have to go up one or two mainjet sizes since it will run much leaner...good luck...

Actually the muffler makes the most difference. Everyone ive talked to said that the muffler makes the most difference for the power of your bike. So actually its not senseless.

And Keith..I only suggested the E-series b/c you talked to me saying you wanted to smooth out the power of your bike.

White Bros Carbon Pro. That is what Factory Yamaha is using in Supercross and Outdoors/Nationals, Reed, Voss, Ferry, and Vuillemin. It's expensive new, lists for $899. I am selling mine, which is new, one ride, not one blemish on entire system! I am down for ACL and will probably buy an 06' YZ after I return to riding. The Carbon Pro is the lightest system you can put on the bike and smooths out the power while increasing it. It doesn't get much better than that! I'm asking $600 obo for my complete system. I have photos if you e-mail me a request for them.

Joe joe_jet@msn.com or PM or 909.472.1755

BTW I didn't mess up my knee on my Yammie...I did it on my old CRF250.

bryan I didnt mean about smothing out my power I want more lo end and hi end power. :cry:


I hate these threads!!! What a bunch of crap. Just want to make me EXPLODE!

WHITE BROTHERS E-SERIES!! are you crazy? that is the worst slip on pipe ever!! there is no difference...if want to get that bike...i'd stick with stock then, you arnt going to tell no difference except it sounds a little different.

I have the Factory 4 slip on with the stainless mid pipe on a 03' 450. It fits really well with the stock header but did nothing for performance. It looks much better and is a lot shorter and tucked in than stock. I would try the power bomb header next. I don't need anymore power out of this bike though.

The Factory 4 is the new version of the titanium 4 slip-on. Try rockymountainatv.com for a really good price.

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