07' yz 450 boggs in low end help??

10 replies to this topic
  • born_2_ride85

Posted March 12, 2008 - 07:50 PM


I just stepped up to the four-stroke world and bought a used 07' YZ450. The bike seems to run well but it just needs some tuning. At first crack of the throttle it boggs but at the mid and top end it rips. When the air temp rises the bike runs great from low to top end. Im just wandering what i need to do to adjust the carb. I bought an after market air/fuel mixure screw thinking that would solve the problem but the problem did not improve.

  • honda123

Posted March 12, 2008 - 07:55 PM


i think u may need to get a bigger jet to richen it.. but ask eddie he should know

  • thumpyz

Posted March 12, 2008 - 08:29 PM


Go with a boysen quick shot or check your jetting.

  • Family Man

Posted March 12, 2008 - 08:35 PM


Did you adjust your pilot circuit?

  • grayracer513

Posted March 12, 2008 - 08:45 PM


To begin with, If you are still busting the throttle open from an idle the way most Pinger People are wont to do, you need to re-educate yourself. That's a situation that simply never comes up when you are actually riding. Learn to roll the throttle, opening slowly at first, adding more and opening farther faster as the engine responds. Once you get this, it will become second nature to you, and your engine will sound as if it exploded to life instantaneously.

You have to be realistic in your expectations. Part of that also is correcting an engine that really does bog more than it should. The first step is to be sure the pilot is rich enough:


That will clear up most of your problem.

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  • Ga426owner

Posted March 13, 2008 - 06:16 AM


Do not buy a Quickshot - these only address 1 problem as the symptom...this product is not the best fix. but a bandaid fix
You have several options:
All involve removing the carb for tuning
1, Remove clean and rejet for your altitude and air temp - check jetting thread for recommendations. This is trial and error and may address the bog but some bog will always be there. Also search the AP Mod topic for a nother DIY tip.
2, Remove carb, clean rejet and add the R&D Float bowl - this fixes a lot of the issue.
3, Remove carb - send to ZipTy Racing for their FCR Carb mod and consider the R&D floatbowl from them - they will tune entire carb - accel pump and quirt duration as well as much more. Call Steve there for full details.
Also get rid of the stock plastic hotstart nut on carb - this will eventuall strip threads and allows moisture into carb from washing etc...Zipty and PC sell these alum nuts
I got tired of always messing with my 03 and 06 carb. I prefer to ride vs always tinkering with carb issues - I sent both to Zipty and have been extremely happy with results - Now all I do is richen or lean for changes in temp/humidity and altitude - and absolutely no more bog.
Good luck with your decision - :thumbsup:

  • Drfletcherdc

Posted March 13, 2008 - 06:45 AM


The temperature affected my 06 a lot. I ran different pilots for summer and winter. And grey is right, learn to roll on the throttle especially through turns to help the rear end stay settled.

  • gdbarr1976

Posted March 13, 2008 - 06:49 AM


Does this bog seem to be there as soon as you start the motor up or does it come on after 5-10min of riding? I am asking this because I am trying to solve a similiar problem with my 06. Has any valve work, replacement or adjustments been done?

  • William1

Posted March 13, 2008 - 12:50 PM


What size leak jet do you have in?

  • Family Man

Posted March 31, 2008 - 10:13 PM


50 tooth rear sprocket will help aot with the low end.

  • Ga426owner

Posted April 01, 2008 - 04:44 AM



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