2011 yz450f yoshi rs4 vs fmf 4.1 rct


18 replies to this topic
  • throttle violence

Posted October 01, 2012 - 10:21 PM

#1

here is a review of these two pipes for the efi yz450f.
my riding is enduro/desert no MX.
i did 30hrs on the yoshi and so far 10 on the fmf
the fmf 4.1 rct is a far better pipe its much lighter the yoshi is heavier than the stock! i couldnt believe it when i took it out of the box was put off straight away.
the yoshi is extremely loud without the insert its near enough impossible to ride i know loud is sometimes good but its an anoying loud so hi pitched especially where i ride where your 4th and 5th gear flat out most of the time in the desert.
the fmf you can run without insert (just straight through) which is what i do and its still very quiet really deep and plesant.(i guess thats the rct ressonance chamber technology)
the yoshi because you need to run the insert (to loud without )still has the same flat top end as the stock...i dont care what bullshit dynos out there say you can feel it. power down low is slightly more than stock.
the fmf just screams with over rev so much fun to ride because no insert needed and the power is still strong down low much smoother than the yoshi no jerkyiness.
also "looks" wise the yoshi is way to big and fat for the yz cosmetics it just dosent look right. dont be fooled by the pictures on the yoshi site that pipe looks shorter but they have lengthened it and its not the pipe that you will get.
the fmf just looks right.
i wrote this so you guys dont spent twice like i did i read in some moto mag that the yoshi was the way to go but its not.
both pipes are excellent build real quality i couldnt fault the yoshi the stickers are a bit weak on the fmf but they have some new ones now that are hard to fall off. where as the yoshi ones are much better quality.
some people say you need to run inserts as they perform better i completely disagree i have done it with trial and error with my ass on the seat and no inserts kick ass you dont see moto gp bikes running inserts in there bikes.
in summary the yoshi is not a bad pipe but the fmf is better.
anyway hope this helps
ps both were slip ons.

Edited by throttle violence, October 03, 2012 - 07:39 PM.


  • HRC

Posted October 02, 2012 - 11:42 AM

#2

I have the FMF RCT 4.1 on my -12 yz450f and absolutely love it ! This motor and pipe combo is one of the best ive had.

Last year I had the Arrow exhaust on my -11yz450 and was very happy with the performance . However, when I tried that exhaust now compared to FMF , the FMF blows me away how much better it performs !

  • throttle violence

Posted October 02, 2012 - 06:43 PM

#3

I have the FMF RCT 4.1 on my -12 yz450f and absolutely love it ! This motor and pipe combo is one of the best ive had.

Last year I had the Arrow exhaust on my -11yz450 and was very happy with the performance . However, when I tried that exhaust now compared to FMF , the FMF blows me away how much better it performs !

i know the engine just sings with this pipe it just keeps powering on its like you say motor and pipe combo is just perfect.

  • titanmx61

Posted October 03, 2012 - 09:38 AM

#4

I just got my FMF JGR Edition 4.1 RCT in yesterday, so as soon as I get it fit up and the bike running right I'll post my results. Good write up on the FMF! I'm excited to get mine on.

  • BBrown626

Posted October 03, 2012 - 07:27 PM

#5

I recently replaced my stocker with the Yoshi RS4 full system. It is fairly loud and I have not tried it with the insert. I think it is quieter than a stock KX.
I rode with the stock system for nearly 200 hours! The Yoshi is a huge improvement! What a fool I was for waiting so long. :banghead:
I can't compare it to the FMF, but I am willing to take your word for it that it is quieter and smoother. I am stoked with the Yoshi.
I went with the Yoshi because of price. The club that I ride with is supported by them and they sold it to me for about half off the cheapest on-line price I could find! Less than a slip-on from any respectable brand.

  • throttle violence

Posted October 03, 2012 - 07:31 PM

#6

I just got my FMF JGR Edition 4.1 RCT in yesterday, so as soon as I get it fit up and the bike running right I'll post my results. Good write up on the FMF! I'm excited to get mine on.

thats an awsome looking exhaust JGR but remove the insert spark arrestor if you want full potential

  • titanmx61

Posted October 03, 2012 - 08:35 PM

#7

thats an awsome looking exhaust JGR but remove the insert spark arrestor if you want full potential

They don't even put it in to start with! They give you the option by putting it in a seperate bag. Ride test coming...

  • grayracer513

Posted October 04, 2012 - 07:06 AM

#8

Properly configured, a spark arrestor will have no detectable effect on performance. With the DRD exhaust I've been running, I can't tell from riding it whether it's in or out.

  • BBrown626

Posted October 04, 2012 - 04:30 PM

#9

Properly configured, a spark arrestor will have no detectable effect on performance. With the DRD exhaust I've been running, I can't tell from riding it whether it's in or out.


WIth the Yoshi I believe you have to have the quiet insert in to hold the spark arrester. Agree with your comment, but I don't believe proper configuration is a choice some of us have.

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  • grayracer513

Posted October 05, 2012 - 06:46 AM

#10

WIth the Yoshi I believe you have to have the quiet insert in to hold the spark arrester. Agree with your comment, but I don't believe proper configuration is a choice some of us have.


Yeah, that's a little different. Depends on how the manufacturer lays stuff out. The DRD I have gives a choice of either the sparky or the quiet insert, which is a little weird, really. Works out for desert racers, though.

  • KJ790

Posted October 05, 2012 - 06:49 AM

#11

Yeah, the spark arrestor for most FMF pipes looks like their quiet insert with a screen attached as well. They do not offer the spark arrestor with any of their larger inserts.

  • throttle violence

Posted December 02, 2012 - 03:15 AM

#12

here is a review of these two pipes for the efi yz450f.
my riding is enduro/desert no MX.
i did 30hrs on the yoshi and so far 10 on the fmf
the fmf 4.1 rct is a far better pipe its much lighter the yoshi is heavier than the stock! i couldnt believe it when i took it out of the box was put off straight away.
the yoshi is extremely loud without the insert its near enough impossible to ride i know loud is sometimes good but its an anoying loud so hi pitched especially where i ride where your 4th and 5th gear flat out most of the time in the desert.
the fmf you can run without insert (just straight through) which is what i do and its still very quiet really deep and plesant.(i guess thats the rct ressonance chamber technology)
the yoshi because you need to run the insert (to loud without )still has the same flat top end as the stock...i dont care what bullshit dynos out there say you can feel it. power down low is slightly more than stock.
the fmf just screams with over rev so much fun to ride because no insert needed and the power is still strong down low much smoother than the yoshi no jerkyiness.
also "looks" wise the yoshi is way to big and fat for the yz cosmetics it just dosent look right. dont be fooled by the pictures on the yoshi site that pipe looks shorter but they have lengthened it and its not the pipe that you will get.
the fmf just looks right.
i wrote this so you guys dont spent twice like i did i read in some moto mag that the yoshi was the way to go but its not.
both pipes are excellent build real quality i couldnt fault the yoshi the stickers are a bit weak on the fmf but they have some new ones now that are hard to fall off. where as the yoshi ones are much better quality.
some people say you need to run inserts as they perform better i completely disagree i have done it with trial and error with my ass on the seat and no inserts kick ass you dont see moto gp bikes running inserts in there bikes.
in summary the yoshi is not a bad pipe but the fmf is better.
anyway hope this helps
ps both were slip ons.

if you want to hear this pipe on my bike in action utube yamaha yz450f power 2011 model

  • throttle violence

Posted December 02, 2012 - 03:17 AM

#13

I have the FMF RCT 4.1 on my -12 yz450f and absolutely love it ! This motor and pipe combo is one of the best ive had.

Last year I had the Arrow exhaust on my -11yz450 and was very happy with the performance . However, when I tried that exhaust now compared to FMF , the FMF blows me away how much better it performs !

i just did a video of the pipe in action utube yamaha yz450f power 2011 model

  • throttle violence

Posted December 02, 2012 - 03:19 AM

#14

I just got my FMF JGR Edition 4.1 RCT in yesterday, so as soon as I get it fit up and the bike running right I'll post my results. Good write up on the FMF! I'm excited to get mine on.

if you want to hear my pipe in action utube yamaha yz450f power 2011 model

  • kiessel24

Posted April 01, 2013 - 11:44 AM

#15

Im looking at getting the FMF 4.1 RCT slip on for my 2010 yz450f. But was stuck between the 4.1 RCT and the regular 4.1. Your review of the pipe was very helpfully, but overall how loud was the pipe? I dont want nothing too loud but still want it to sound mean lol. And someone also said that the sparky and quiet insert are all one piece??

Edited by kiessel24, April 01, 2013 - 11:46 AM.


  • zeuszuki

Posted April 01, 2013 - 10:29 PM

#16

A mate of mine put the FMF 4.1 slip on onto his '10, killed the low end but let it rev out. He fitted the insert to help reduce the noise and felt it helped bring back some bottom end. I suspect the insert added back pressure and the '10 base map is not as compatable as the '11 .
Anyone else able to add to the above? This only one persons experience of course.

  • 2012yz450f

Posted September 06, 2015 - 12:03 PM

#17

I just bought my 2012 yz450f   i just installed my new Yoshimura RS-4D Pro Series Titanium Full System Exhaust, I sure feel a lot more bottom end to mid range, but no top end, and I believe I have to get it tuned. I cant find anywhere for proper mapping for this set up? Do you guys know where?

I wondered if this FMF is supposed to be better than this set up?

  • billygildark5007

Posted September 06, 2015 - 08:01 PM

#18

I've had both on my '11 and I'd have to vote for the rs4. It is heavier and the top is still "flat" but by then it's time to shift. Low and midrange seem more responsive. Mx outdoor riding.

  • billygildark5007

Posted September 06, 2015 - 08:03 PM

#19

I just bought my 2012 yz450f i just installed my new Yoshimura RS-4D Pro Series Titanium Full System Exhaust, I sure feel a lot more bottom end to mid range, but no top end, and I believe I have to get it tuned. I cant find anywhere for proper mapping for this set up? Do you guys know where?

I wondered if this FMF is supposed to be better than this set up?


Check out the stickies on the top of the page for your maps.





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