Rejet again???


5 replies to this topic
  • ak567

Posted December 09, 2008 - 03:53 PM

#1

I got a 08 wr450 and it has the ASI removal kit, grey wire snipped and throttle block removed. I need to know what size jets are in the ASI removal kit for the rejet for the carbs. The reason for this is I got a full fmf exhaust system I am going to install . Is there any need to rejet again From MY previous set up? I also had the insert removed from the pipe and the box lid removed. Bike ran perfect with no flat spots.(the exhaust is a fmf mega bomb header with a 4.1 muffler.)

  • William1

Posted December 09, 2008 - 04:13 PM

#2

You will need to go up a size or two in main jet. Starting with the recommended main, remove the airbox door and go for a ride (bike fully warmed up). Is it better or worse?
If it is better, you need a smaller main.
Go down one size, replace the airbox door, ride. Remove the airbox door and test again. Better or worse? If better, go down a size again. Keep repeating this till the test with the airbox door is worse.

If it was worse with the airbox door removed, tape over 1/3 of your airbox opening then test.
If it is worse now with the tape and was worse with the airbox door off, your main is just right. You are done!

If it seems better, you need to go up a size in main jet. Test it again (remove the tape). Replace the tape, test again. If with the tape on it is better, go up another size in main. Keep repeating this till having the tape on is worse than with it off.
To finish up and ensure you are set accurately, retest the bike with the tape off, ride it, then remove the airbox door. Best performance should be with the airbox untapped, airbox door on.

Remember, the main only operates at WOT. Ideally, you want to be in 3rd or 4th gear doing the tests, hitting max revs (just shy of the limiter) for at least 10 seconds to get an accurate representation of the jet status.

  • ak567

Posted December 10, 2008 - 04:03 PM

#3

This sounds like a really accurate and worthy method, but I was planning on getting my dealer to do it as a one shot deal. Thats why I was hopefully trying to find someone with a very similar setup.

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  • Saber9

Posted December 10, 2008 - 07:18 PM

#4

I'm not laughinging at either one of you. But I don't care who you are, that was just funny.:thumbsup: :smirk: :usa:

On the other hand, many of us will benefit from that exchange. I love it! Thanks guys.

  • snaggletooth

Posted December 11, 2008 - 01:02 AM

#5

Getting into the carb on my 07 required me to remove the subframe and rear shock (must be a better way). Reading about doing all of that carb work to get it just right will give me bad dreams tonight.

  • ak567

Posted December 11, 2008 - 01:25 PM

#6

Exactly, It would cost me like 350 buxs on labour alone. I wouldn't mind the trial and error route if the carb was easily acessable. So please someone help out a fellow moto rider and post sumptin up. I cant really start till a few months cuz wer are currently in winter mode, but this is the perfect time to gather information.




 
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