2011 kx450f pipe reviews?

28 replies to this topic
  • Slow250

Posted February 27, 2012 - 07:04 PM


Just got a Factory 4.1 with TI megabomb on Ebay for a 380 shipped. Listed as great shape, so hopefully I lucked out. I'll post feedback in a while.

  • Wes Woodin

Posted March 09, 2012 - 07:45 PM


got my FMF RCT TI 4.1 today! New version otd $650 all day long. Oh, I'm a fast rider, but it's mostly for looks!

  • wes513v

Posted March 13, 2012 - 06:34 AM


i dont speak down on people, i put my opinion out there', and my opinion is the OP would be better off spending $500 on ride coaching, fuel, oil brake pads chains and sprockets or suspension setup, or if he's after performance a set of hot cams or head porting with an appropriated engine map will give greater gains for less money without an obnoxious engine note which damages the sport for everyone as well as the offending bike, if you don't like hearing my opinion's, then feel free to block me :thumbsup:

i absolutely don't support any idiot who thinks "noise is not an issue" because he "kinda likes loud pipes" knowing full well that the biggest threat to this sport is excessive noise.

A recent article I read in MXA calls BS on your engine mods statement. They got the greatest performance increase from a pipe, with decreasing results as they tried cams, h/c piston and re-maps. So it would seem that the op's original desire for a new pipe, increased noise aside, would be the logical next step and best bang for the buck. And he doesn't have to tear down a motor unnecessarily. Granted, the test mule was a crf250, but I am sure the results would be similar on the KX. And the newest issue of Dirtbike has 3 of the pipes the op is looking at tested on a KX450, so he can get the info on those right there.

  • felix 222

Posted March 13, 2012 - 04:46 PM


4.1 installed. Will report performance after next ride.

Posted Image

Edit: how is the "new" version any different? Judging from FMF's website, it appears they changed the sticker and possibly darkened the anodized blue. the part # remains unchanged so I'm assuming changes were merely cosmetic, or so I hope lol

Edited by felix 222, March 13, 2012 - 04:48 PM.

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  • wes513v

Posted March 14, 2012 - 07:39 AM


I thought Bill's had faded into obscurity and were only available on Ebay, but there was a test in my last issue of Transworld (if I remember correctly, hasn't been uploaded to their site yet) that rated them well. They're cheap too. Full system for about 400 shipped. Anyone try one yet?

Yeah, but they are a full race system rated at 98 db+. At least the ones on ebay. You could go Leo Vince X3 or Motoworks for the same price and have something that has replaceble inserts for sound. In Cali, some state areas sound check.

  • Johnny2/4stroke

Posted April 22, 2012 - 01:43 PM


Anybody ever hear of, or happen to have a system from this company: http://jemcoexhaust....uct_Catalog.pdf
http://www.jemcoexha...m/products.html They make a nice upswept pipe for most 450's I'm looking into getting one for my 11 kx450.

  • GreenMachineExtreme64

Posted July 14, 2012 - 07:17 AM


If you're going to put a full exhaust on that thing, you should definitely consider remapping the FI to accomodate the high performance pipe. It will create a leaner condition and remapping the FI is an almost must. The FI on the KX is open loop, which means it's not going to automatically adjust for the new exhaust like a closed loop FI would. You can actually get more performance out of the KX by tweaking the FI than you can with just an exhaust. It's pretty amazing what that little computer can do.

The PC and FMF pipes are both great. I run the FMF 4.1 RT w/ Megabomb header for moto and the Powerbomb header for off-road along with two different FI mappings for each condition.

A few shops usually have the FI calibration kit and will remap the ECU for you for usually around $50 or so. You can also just mail the ECU to a place like Precision Concepts and they'll remap it for $69. They've done a bunch of testing and have good maps. That's what you're paying for... lot's and lot's of testing. It's a 5 minute job. AS Racing has a drive-up FI calibration kiosk at his shop in Santa Clarita. Now that's cool.

Don't some of the pipes come with a means to do the remapping yourself?

  • Justin Hambleton

Posted July 15, 2012 - 08:17 AM


Don't some of the pipes come with a means to do the remapping yourself?

Not to my knowledge. The Kawi FI mapping kit is $400 alone of you can get something like the Dynojet Power Commander: http://www.powercomm...ng_default.aspx

  • GreenMachineExtreme64

Posted July 15, 2012 - 10:37 AM


WOW, after $750 for full exhaust, then having it mapped for another $400. GEEZ!

I was planning on getting a header and powercommander for my street bike, first, but after this...........

Keeping the stock pipes is sounding pretty good about now. LOL

ANyway, the sound is not a concern for me. I don't give a rip how loud it is, to tell the truth.

I was merely wanting the best priced pipe that gives the most overall power increase thoughout the powerband range.

From what I"ve read, I was leaning towards the megabomb FMF. ???????????

Edited by GreenMachineExtreme64, July 15, 2012 - 10:42 AM.

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