More '08 Stock Muffler ?'s

sorry, if i would remove both cones on the 08 muffler, is the bike better all around?

Oh man... Sorry if I confused you but I was simply making a joke.

As indicated in the thread I linked to, I replaced the '08 exhaust with one from an '06. In doing so, I effectively 'replaced both cones' :thumbsup:

ok, no prob, i was die hard on finding out what i could do, but in other words,,,,the 08 muffler is the worst piece of crap made, espeicialy since an older models exhaust systems can out perform the new one, whats yamy thinking??

ok, no prob, i was die hard on finding out what i could do, but in other words,,,,the 08 muffler is the worst piece of crap made, espeicialy since an older models exhaust systems can out perform the new one, whats yamy thinking??

Well, it's up to you really. I really liked the '08 power for a while. I would even be cool with it now if I could count on it holding up. The thing just burns through packing and is hard to maintain. Add to that the lack of bottom and it really does suck.

That being said, I am still unsure whether or not my lap times are better with the new pipe or not. I suppose we'll have to wait and see.

,,,,the 08 muffler is the worst piece of crap made,

Wow, this thread still has legs. I agree, no bottom with this muffler. I look around at the track and see most bikes have stock exhaust but most yamahas have been changed. Probably because of the performance, but they are really loud. My question is ...and a serious one....why fiddle with it? Why not just go out and get an aftermarket unit. Is it the cost? The noise? Is the performance that much better to shell out the bucks? Is it that we really like the short unit?

I think I would like to try a slip on because the stock header pipe is really nice (Ti) with a good sheild. But the slip on's are still pricey.

It looks to me like the 09's will have the same unit. I really did not think they would spend all that R&D time plus tooling just to dump it after a year, even if they knew it was underperforming. Maybe its a conspiricy to keep the aftermarket pipes in business.:thumbsup:

Thanks Y'all

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It looks to me like the 09's will have the same unit.

In Australia the '08 YZ450F had the shorty muffler and straight header pipe.

The '09 YZ450F has a long muffler (actually 15mm longer than the WR450F believe it or not) and the "powerbomb" style header pipe.

The '09 header pipe weighs in at 893 grams, the '08 style is 562 grams.

The '09 muffler weighs 3000 grams, the '08 is 2450 grams !

So, it appears that Yamaha have made the exhaust system 881 grams heavier this year!

The '09 header pipe:

2009_YZ450F_PowerBomb_header.jpg

(I just picked up a complete, one ride old, '09 YZ450F system for about $US80 off eBay!)

Greg

This pipe is on my 08 450'f??

This pipe is on my 08 450'f??
Maybe not. The Euro models mostly shipped with the older type straight-through "glass pack" muffler, which typically extends 100-150mm beyond the number plate. With that system, the header was like the one shown in the post above. U.S. models came with the short, baffled glass pack shown in the cutaway. It extends maybe 25mm beyond the plate and uses a straight header. Models shipped to parts of Asia, South America, and Australia could have either one, it seems.

The longer, straight through system performs far better in the mid range than the U.S. shorty does.

Yes I know that the muffler is longer, but the header pipe is the same as picture shown above from the '09 pipe.

I bought already a new pipe, but i'am gonna make the EURO silencer 7cm shorter and remove the 2cones.

But in europe, the silincer is smaller than the pipe with the holes.

So you have 2 cones+1endcap. I also have to remove thus encap.

(euro 94Db limiit:moon: )

.

The longer, straight through system performs far better in the mid range than the U.S. shorty does.

That statement may influence my choice of muffler when I decide which one to fit to my WR450F (I have four Yamaha systems in stock here!). Shame, because that "shorty" is so light compared to anything else!

Anyway, back on subject......I had a quick look at the '09 YZ450F (long) muffler I bought when I got it home last night....

Interestingly, looking in from the back it has at least one of those perforated cones inside, sounds just like yours Lorre79, so Yamaha must think they are on a good thing there! I'm assuming there is another one inside that (surgery will confirm this I'm sure.)

The entry pipe of the unit is around 43mm diameter but the exit tip of the muffler looks about 25-30mm diameter, so it is quite flow-restrictive in stock form. The gases would leave at a higher velocity, but still have to be pushed out under increased pressure.

Greg

.......I had a quick look at the '09 YZ450F (long) muffler I bought when I got it home last night....

Interestingly, looking in from the back it has at least one of those perforated cones inside, ...

Then apparently the Euro Long muffler differs from the '07 U.S. type, which was straight through.

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I am gonna make the EURO silencer 7cm shorter and remove the 2cones.

I also have to remove this encap.

I'm thinking I might follow your lead there too Lorre79, but I will press the end-cone out and make a custom-made, 43mm diam insert/tail-pipe to suit.

I'm banking on the muffler having a straight through perforated tube, 43mm diameter around those cones, (like the shorty one does)so i can convert it to a standard design muffler internally!

Man, this is all so interesting. I love investigating and modifying these Yamaha mufflers. I have no interest in buying an aftermarket one!

Greg

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More tid-bits of YZ450F exhaust info.....

In regard to Aussie release bikes:

The '07 - '08 straight header was 43mm ID

The '09 "powerbomb" header is 39mm ID

The plot thickens!

What are Yamaha up to?

Greg

.

Man, this is all so interesting. I love investigating and modifying these Yamaha mufflers. I have no interest in buying an aftermarket one!

Greg

I thought just riding and not getting hurt while doing so was enough of a hobby ---- but you sir, are pushing it to the next level:thumbsup:

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I thought just riding and not getting hurt while doing so was enough of a hobby ---- but you sir, are pushing it to the next level
\

:moon::lol::p

It's an addiction!

You know, I have been riding and/or racing for almost 38 years. I've had countless crashes, and the worst injury I've ever had in all that time was a broken collarbone (touch wood!).

:thumbsup::p:p

Greg

you guys are die hard crazy about modifiyin tha shorty!!! i gave up n threw a full dr.d on mine for 445 shipped to my door off this site, sorry guys, but i have to say that is the best way for bottom end, just wonderin, you guys move you clip to the 4th pos. and put in the 165 main jet, that REALLY gave er more umf, honest! but any way, i have my stock system for sale here and you guys make a bad mistake, you now know were to get another one:thumbsup: :thumbsup:

.

you guys are die hard crazy about modifiyin tha shorty!!!

j-ripper,

It's the long YZ muffler we are talking about, not the shorty.

Modifying the shorty is asking for trouble (ie. excessive noise) in my opinion.

Greg

you guys are die hard crazy about modifiyin tha shorty!!! i gave up n threw a full dr.d on mine for 445 shipped to my door off this site, sorry guys, but i have to say that is the best way for bottom end, just wonderin, you guys move you clip to the 4th pos. and put in the 165 main jet, that REALLY gave er more umf, honest! but any way, i have my stock system for sale here and you guys make a bad mistake, you now know were to get another one:thumbsup: :banana:

My '08 came with the shorty, stock. I bought my bike used; it has FMF Ti pipe. Has really good low-end with that pipe, but it IS loud, good for closed-course competition only. We ride in Colorado mtns at least every-other year . . . I might mount stock shorty "quiet" pipe for that.

Question:

Not counting altitude difference, what jetting changes would be necessary going from FMF pipe to stock pipe for my '08450? (i.e., one size leaner main, one clip leaner needle, etc. ???)

Good thread Gray, thx.

FWIW the guy I bought it from told me (but I'm from Missouri . . "show me";-) what jets are installed and it's close to what's in the thread.

I will have to see for myself what's in there (only thing I've done is move needle one clip richer to #4 pos from #3) but it's running so good now, I'll wait till summer probably.

Euro models are down on power as well. 08 and 09 yzs have 4-5 hp less power than kx or sxf 450.

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