Would Like More Throttle Response And Low End Out Of My 09 Yz450

7 replies to this topic
  • JESSEH833

Posted May 13, 2009 - 07:06 PM


Already Got Full Exhuast. Jetted Perfect. One Tooth Bigger On Sprocket. Please Help. Would A Quickshot Help!

  • grayracer513

Posted May 13, 2009 - 08:29 PM


Jetted Perfect.

If that were true, you'd have no complaints about throttle response. You don't need a QS. You need to tune the AP, and possibly go with a needle with a main diameter one size smaller.

  • Ga426owner

Posted May 14, 2009 - 05:47 AM


don't shoot me grey - Here are a few ideas that cost 100-250 bucks

I have been hearing some good things from folks that are using the Loudmouth Airfilter system for better lowend - I have yet to try one but would offer my bike to test one....hint hint Loudmouth

I also have seen the the R&D Floatbowl/Adj LJ as well as the Merge Racing Adj LeakJet kit add better throttle response.

On my 03 I have tried a quickshot, powernow and these help but I found the JD Jetting kit offers better throttle response and I am testing the oring mod on my 03 currently to see what the benefit is. (I still want to test a R&D Floatbowl to see if there is a benefit to having a Adj LJ on a none equipped FCR carb on the 03)...anyone have one laying around?

  • grayracer513

Posted May 14, 2009 - 07:09 AM


I really doubt there is any benefit to the Loudmouth air filter, but some solid independent tests would be nice to see.

Devices like the Power Bowl and the ALJ dont really accomplish anything that can't be done with the stock carb as equipped. It's just accelerator pump tuning. The Merge ALJ will make the process faster, though, and that may make it worth the price. The Power Bowl is just too expensive, and the bowl itself offers no advantage of any kind over the ALJ. If R&D has a pump cover with an adjustable leak like the Merge ALJ, the two could be compared.

Another thing that can be added is the stiffer AP linkage spring from Merge. It does what the O-ring mod does, but does it in a much more workmanlike manner.

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  • Justin89

Posted May 14, 2009 - 09:25 AM


Replace your cams with OEM 06' cams:thumbsup:

  • husqy360

Posted May 14, 2009 - 02:40 PM


what about cutting the air filter cage screen ?

  • Justin89

Posted May 14, 2009 - 03:44 PM


what about cutting the air filter cage screen ?

I dunno if that works either way. I've seen people with hondas catch on fire..no joke

  • grayracer513

Posted May 14, 2009 - 04:03 PM


what about cutting the air filter cage screen ?

Has no effect on YZF's dyno tests done by Doug Henry's SM crew tried several different air box configs and ended up leaving the screen in.

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