02, 426 backfire on decel and idle cut out-erratic

5 replies to this topic
  • YZF426WFO

Posted April 06, 2004 - 06:54 PM


Hey guys recently purchased this bike from Optimum Power technologies. The bike was retrofitted with a fuel injection kit and a programmable ignition with several MAP selections. Any way I recieved the bike totallly back in STOCK form.
The problem I am having is when the bike idles for approximately 25-30 seconds or less it just pops out and dies. I would assume that along with the back firing on decel with the throttle closed this indicates somewhat of a lean condition?? maybe? I checked and cleaned the carb and I noticed that the pilot screw was turned out 3 full turns!!!! It currently is a 1.5 now with about the same results. When I had the carb apart I cant remember if i double checked to see if the o-ring was in tact inside the pilot jet screw or not. Oh well maybe someone has an idea or direction to steer me, thanks ~~~~rob

  • berudd

Posted April 07, 2004 - 09:28 AM


Did they change the jetting? My 02 has stock jetting and would idle until it blew coolant if I let it. If your fuel screw is close, check the jetting. Hmmm, I wonder if a plug that is seriously out the correct range would affect this. I run a CR7E or CR8E in mine.

  • YZF426WFO

Posted April 07, 2004 - 06:11 PM


I believe that the jetting is totally stock now. Yes my 01 426 would also idle till it would puke coolant out too. I'm not sure about the fuel screw though, like I said the pilot screw is turned out 1.5 turns, and im also running an NGK cr7e. I'll just have to rip it off the bike again and record what exactly I find as far as numbers go.

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  • berudd

Posted April 08, 2004 - 04:35 AM


I think we are talking about the same screw, maybe I am wrong. The one on the bottom of the carb that no normal human can reach.

  • Hick

Posted April 08, 2004 - 06:08 AM


Sounds like it coulb be another upside-down slide.

That's my first guess.

  • YZF426WFO

Posted April 08, 2004 - 06:16 PM


Really?? HMmmm the carb is coming off tomorrow I want to get the bike idling right. The funny thing is besides the 2 probs it rips!!

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