Uhhh....what could have changed?


4 replies to this topic
  • 02WR426Cali

Posted March 28, 2010 - 01:25 PM

#1

Ok let me start by saying my WR is just like a YZ now with a few mods and all the free ones of course.

My bike ran great but it would sloooooowwwwly leak fuel out the overflow while it would sit in storage. It didn't dump out like when the float level is off or when the needle/ seat is messed up. So I dug into the carb and replaced the oring that goes on the seat. It was old, hard and brittle so I figured it must have been leaking fuel around that and letting it get into the bowl while it sat. Ok fine but I run the bike for a minute or so when I put it away while the petcock is off. So there shouldn't be lots of fuel to drip past this oring. So I thought about it and I replaced the seals in the petcock as they probably were not sealing in the off position. Turns out they were hard and brittle too. I also replaced my easy adj fuel screw with a new one as I was missing a washer and needing an oring that are not easy to find by themselves.

Alright so I got the leaking to stop. But now it backfires now a little when starting and runs lean as soon as you crack the throttle. It idles fine once started but it's lean because it tops out at like 1/3 throttle. I took the carb back off to inspect and everything was clean no clogged jets.
I did not mess with the jetting as it ran good before.

I'm thinking that maybe it ran rich before due to all the leaky spots, but now it's not getting enough with everything sealed up?

I also checked the airboot on the head for air leaks spraying carb cleaner and no change in idle so that is fine

  • BAHeron

Posted March 29, 2010 - 09:30 AM

#2

A buddy had somewhat of the same problem on his YZ converted to WR, The dealer found an o-ring in the carb dry rotted. I think it was on the pilot jet. His would run, but wouldn't start when warm. It also leaked gas from the overflow when kicking or sitting. $200 in shop labor for a .10 cent part, but it runs good now! I'd say to change everything rubber in your carb, if you haven't already. Hope this helps

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  • Birdy426

Posted March 30, 2010 - 10:18 PM

#3

Did you put the plate on the carb slide on upside down? Been there, done that, got the tee shirt...similar results.

  • Pooley

Posted March 31, 2010 - 04:52 AM

#4

A buddy had somewhat of the same problem on his YZ converted to WR, The dealer found an o-ring in the carb dry rotted. I think it was on the pilot jet. His would run, but wouldn't start when warm. It also leaked gas from the overflow when kicking or sitting. $200 in shop labor for a .10 cent part, but it runs good now! I'd say to change everything rubber in your carb, if you haven't already. Hope this helps


Agree with this. I had it happen last spring. The o-ring around the valve seat had dried/hardened so much it would no longer keep a seal. I couldn't get the bike started because it was always overflowing the carb. Unless you find a generic o-ring from a hardware store that fits, you will probably will have to buy the entire needle valve assembly.

  • 02WR426Cali

Posted March 31, 2010 - 06:18 AM

#5

Birdy: I didn't even mess with the upper half of the carb as it was running great before, I just was into the bowl and such.

Pooley: That is the Oring that I did replace as mine was dried and brittle as well.

Posted in original post: "So I dug into the carb and replaced the oring that goes on the seat."




 
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