Backfiring


6 replies to this topic
  • taksx

Posted August 08, 2005 - 03:27 PM

#1

Hey guy's want to see if you (WR Masters :D ) can help me with this one.

I have a 05 WR450, When i bought the bike my dealer gave me the
GYT-R AIS kit that came with a throttle stop,48 pilot,needle and the
removal kit.

I installed the kit did all the mods put the needle clip on the 4th notch, replaced the 45 stock pilot with the new 48. And took it a step further and got the zip ty mix screw,I have it at sitting at 1.75 turns out. I did not replace my main jet its still stock (165).

The bike runs absolutely flawless, Except when i let go of the throttle it back fires on me. I can be riding or just warming it up, i give a little gas, let go, and it backfires on me. Or full race mode and its pop'ing like crazy only when i let go of the gas.

My questions are this.
Should i ditch the GYT-R needle and get the JD kit?
Replace my Main jet?
Or do it have to wrench it and adjust my timing?

Have any of you had good or bad luck with the GYT-R kit? Or did you know they made one:excuseme:

I'm also having somewhat of an issue with the idle. I can idle for a min or so and it dies on me. The trippy part is that it revs up and down up and down and its dies after that.
Is this related to my backfiring? the bike only has 121 brake in miles.

I'm riding in 3000' to 4000' temps 70 to 90+, Out in the California high deserts.

Help another brother out here this backfiring is driving me crazy :D

Thanks a bunch Eddie :D

  • Dodjy

Posted August 08, 2005 - 04:16 PM

#2

I think this is normal, lean at low throttle openings. Mine pops on backoff as well. You could probably get rid of it by richening up the pilot jet or try opening up the mixture screw a little more but be careful not to go too rich or you will foul your plug if you leave it idling too long. The main needle will only change the 1/4 to 3/4 throttle mixtures. If you haven't disconnected the grey wire, try that. It fixed the same idle problem on my bike. Also there have been a few posts on fiddling with the diaphram on the side of the carby (is there to lean up the mixture when you get off the throttle). I prefer to have a lean idle 'caus changing the plug out in the bush is a pain. The WR naturally won't like to idle too long because of its state of tune (low intake vacuum at idle) so don't expect it to sit there for more than a minute or so idling happily.

  • farkawi

Posted August 08, 2005 - 05:11 PM

#3

Jetting seems to be peculiar to each bike and circumstance. I've had jetting gurus tell me that my #50 pilot jet is a bit rich for the altitudes up on the passes >12,000 ft. However it is working so far with no fouled plugs. I suspect the '05 was pretty lean out of the box so you California people could get those green pasties. Indy posted a good guide at the top of this forum in the jetting sticky. Check it out.

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  • rtrolli69

Posted August 08, 2005 - 08:03 PM

#4

I had the same problem,only I made it worse by installing an after market pipe it would absolutely drive me nuts every time I rolled out of the throttle..??!!!!###I took Indys advice on his jetting chart& ordered the AIS removal kit off of this web site,re jetted with the JD kit,my elevation is 4200ft here in N.M.,my pilot is a #50,168 on the main jet,zip ty fuel adjuster is 1,3/4 turns out..red needle in the 5th position.all free mods&gray wire clipped,also scary fast power plus system.once I put the removal kit & rejetted,NO MORE POPPING&BACKFIRING!!!!the jetting helped performance as much as the pipe did.maybe this will help you..Russ

  • taksx

Posted August 09, 2005 - 06:23 AM

#5

:D Thanks guy's

I seriously thought i had a bigger problem than just a mis jetted carb.
I'll have to get a JD kit, get that GYT-R needle out of there and re-jet
via Indy's advice.

Again, Thanks :D

  • RichBaker

Posted August 09, 2005 - 02:47 PM

#6

I'm also having somewhat of an issue with the idle. I can idle for a min or so and it dies on me. The trippy part is that it revs up and down up and down and its dies after that.
:D

This sounds like you have an air leak....check the AIS removal kit install and make sure the carb is tight at the front(engine side) joint.

  • RichBaker

Posted August 09, 2005 - 02:49 PM

#7

I prefer to have a lean idle 'caus changing the plug out in the bush is a pain. The WR naturally won't like to idle too long because of its state of tune (low intake vacuum at idle) so don't expect it to sit there for more than a minute or so idling happily.

My 03 WR450 will idle all daylong at a steady rpm...if I let it. But I don't cause I don't want to overheat it...




 
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