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Hopsrev86

2010 yz450f aftermarket exhaust

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I just got a 10 yz450 and i am looking to get a aftermarket exhaust. I was wondering what people have tried and how it works. I have the yamaha tuner thing. I am a B rider.

thanks

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According to Motocross Action:

"We tested FMF , Yoshimura , Pro Circuit , GYTR, DR.D , Vance & Hines, FMF and Akrapovic systems and felt that every one of them increased over-rev while taming the barky throttle response off idle. Most MXA test riders were split between the more powerful Yoshimura or smoother Akrapovic exhaust. "

I have a friend who has the FMF and says it smoothed out the low and let it rev more. He uses the stock mapping.

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According to MRD Racing, the problem with the stock pipe is that the muffler utilizes a sudden and significant reduction in diameter at the tip to reduce sound. He says this causes the drop in top end, and that there is no problem with the OEM header.

To that end, he builds a slip-on for the 2010 which compares favorably with a full system at far less expense. Something to look into.

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I also have a Yosh slip-on. The thing I was looking for most was increased top end power. The stock system (as you have probably realized) signs off a bit too soon. It might work well on small supercross tracks or for riders who enjoy shifting alot. The Yosh muffler is a winner because it delivers exactly what I need. It's actually marginally heavier (I'm talking a few ounces) than the stock muffler but it's shorter than the stocker and any other aftermarket slip-on I've seen. It's a winner.

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According to MRD Racing, the problem with the stock pipe is that the muffler utilizes a sudden and significant reduction in diameter at the tip to reduce sound. He says this causes the drop in top end, and that there is no problem with the OEM header.

To that end, he builds a slip-on for the 2010 which compares favorably with a full system at far less expense. Something to look into.

Gray,

Have you seen any dyno results or reviews of the MRD?

I don't doubt it flows better than stock, but how does it stack up to the others?

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No, just what Dave has said about them. He may have some of that info. He said it produces something over 1 hp over the stock unit on top. At this point, I think you'll need to ask him for anything further.

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I'm happy with my Dr. D stainless, saved 1lb and pulls longer. But after reading the MXA shootout I would have to consider the Yosh next time.

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I purchased the slip on FMF Q4 after the second time riding mine, so I can't really say if it made the bike faster or not. What it did do was add a spark arrestor for the trails and such that I frequent as well as keep the exhaust a bit quieter/better/deeper sounding. I have had zero issues with it so far.

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motojase is the production PC pipe have the expansion chamber on the headpipe as well?I know in the catalogs they show it but that doesnt mean anything.

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motojase is the production PC pipe have the expansion chamber on the headpipe as well?I know in the catalogs they show it but that doesnt mean anything.

Sure does mate, looks sweet too, will post a pic for you.garage.php?do=viewattachment&attachmentid=87195

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those are resonator chambers ( its a 50 year old exhaust component design ) and the testing I have done on them makes me think they are nothing more than eye candy , pipes with them dont make any more power and arent any quieter at full throttle than pipes with out them

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Are you guys running full systems or slip-ons?

I need a spark arrestor and I'm not real fond of spending $150 for a simple end cap when I can buy power + function for $300 or less. But I don't want to spend the extra money if a slip-on doesn't really net much of a power gain.

2010 YZ450F, just to clarify

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those are resonator chambers ( its a 50 year old exhaust component design ) and the testing I have done on them makes me think they are nothing more than eye candy , pipes with them dont make any more power and arent any quieter at full throttle than pipes with out them

My 2-stroke has an expansion chamber:banana:

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those are resonator chambers ( its a 50 year old exhaust component design ) and the testing I have done on them makes me think they are nothing more than eye candy , pipes with them dont make any more power and arent any quieter at full throttle than pipes with out them

Properly configured, they do tend to flatten and extend the torque curve somewhat, though.

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Properly configured, they do tend to flatten and extend the torque curve somewhat, though.

maybe on a cirtain bike , but from what I have seen on the dyno it didnt happen on the bikes I tested , and they are allways in the spot where they fit and that just cant allways be the most effective spot timing wise to effect power , I like you Gray , your straight up and no BS and a asset to this forum , I just havent seen any proof that these resonators are anything more than eye candy

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My comment goes back to my experience with my '03 YZ450 and an FMF Ti4 PowerBomb. That bike, with the stock exhaust , was notorious for its "hit" at around 8000 RPM. The "hit" turns out to have been a dip in the curve, a soft spot, if you will, not a sudden spike. The recovery to the interrupted power curve made it seem like a hit. The PB header eliminated the dip when used with either the FMF or OEM muffler, and the bike pulled harder below 8K than without it.

The complete system, tested by a third party, only produced .6 more HP than stock, but the power was measurably broader, easier to manage, and over a full HP was gained at 5000.

This may not apply to other models, and I see nothing to argue with your point about no extra peak power being gained.

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My comment goes back to my experience with my '03 YZ450 and an FMF Ti4 PowerBomb. That bike, with the stock exhaust , was notorious for its "hit" at around 8000 RPM. The "hit" turns out to have been a dip in the curve, a soft spot, if you will, not a sudden spike. The recovery to the interrupted power curve made it seem like a hit. The PB header eliminated the dip when used with either the FMF or OEM muffler, and the bike pulled harder below 8K than without it.

The complete system, tested by a third party, only produced .6 more HP than stock, but the power was measurably broader, easier to manage, and over a full HP was gained at 5000.

This may not apply to other models, and I see nothing to argue with your point about no extra peak power being gained.

if both the headers were made of the same material and gage and had identical dimentions other than the PB I would say that the PB helped you , the thing is that some guys think they are getting all the perf. from the PB when its the entire system being better than stock and would still be better even if the PB was left off the header

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I purchased the slip on FMF Q4 after the second time riding mine, so I can't really say if it made the bike faster or not. What it did do was add a spark arrestor for the trails and such that I frequent as well as keep the exhaust a bit quieter/better/deeper sounding. I have had zero issues with it so far.

I have the same slip on and must say for the price I'm extremely pleased. I wasn't looking for something that could save me weight, but instead add performance and this pipe seemed to do exactly that. It also made the bike more quite but not by much without the optional insert. Either way I'm pleased with this choice. Gives the bike more rev end smoother low end :smirk:

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