2002 WR426F questions

5 replies to this topic
  • DanO22

Posted March 26, 2004 - 06:23 PM


I just picked up my first thumper (2002 WR426F). I have a couple of things I have noticed that I dont understand.

1. I have a Big Gun header and exhaust, when the bike is running the header coming out of the cylinder turns real red (I mean this is some heat). It gets so hot that it makes the kick starter very hot. The pipe is pretty red all the way to the kick starter. Is this normal? Should I be concerned? I certainly am worried about getting burned.

2. The bike seem to backfire significantly when I let off the throttle or when I rev the bike. I dont know if this is just a four stroke thing or if it is a problem. The bike has a big gun exhaust, no air box mod, no grey wire, no jetting. What should I do.

I realize for you TT vets these may be some very rudimentary questions, hopefully I dont bore you to badly.

With this new bike I am sure I will have many more questions.

I have a broken collar bone so I cant ride for 5 weeks. I have ordered all new plastics, graphics, a scotts triple clamp and stabilzer. I will be selling my RG3 top clamp if you know of anyone that wants one. Seems to be very plush and takes alot of the vibration out of the bars or so I have been told.

Well thats it for know, your posts are appreciated.

Dan :)

  • tctrailrider

Posted March 27, 2004 - 02:48 AM


If you let the bike idle for more than a minute, its normal for the head pipe to glow. Once you start moving it should go away. The glow should only be in the first 6 inched from the head. More than what would indicate that you are lean on the pilot jet. Can you post your jetting?

  • DanO22

Posted March 27, 2004 - 05:51 AM


The jetting on the bike is the stock jetting, I am not sure what the settings are so I will see if I can look them up.

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  • oldbones

Posted March 27, 2004 - 06:11 AM


DanO, it is normal for the header to get red hot, at night, and when you are parked or going slow. But, not all the way to the kicker. More telling may be your backfiring, which may be "lean pop". These two sypmtoms together make me think that the bike is too lean.

Course, I don't know a thing about how to fix it, but from talking to others, I wouldn't hesitate to buy the JD jetting kit from the TT store, then log on here and get help setting it up.

Have fun! :)


Posted March 27, 2004 - 06:49 AM


Congrats on the new bike.Like everybody says it sounds like it is lean.Best way to fix that is the jd jetting kit.But I coud not afford one yet.I have a full white bros.system on my bike.So I just put a 170 main jet and moved the clip on the needle to #4 position mine seems to run real good.So maybe try that if you don't get the JD jetting kit. :) :D

  • DanO22

Posted March 27, 2004 - 12:21 PM


I have ordered the JD jet kit from TT. I am also draining all the current gas from the system and cleaning it out. Current contents are six months old according to the guy I bought the bike from.

I just rode the bike down the street yesterday, coming from a KDX200 the power of this 426 is amazing. This thing can scare the cr*p out of you if your not careful. Lots of power compared to the 200, this should be a blast provided I dont get myself killed :)


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