Troubleshooting 07 wr450



10 replies to this topic
  • Noobtastic14

Posted January 24, 2016 - 04:56 PM

#1

I just can't seem to wrap my head around this bike right now.  

 

I bought it used in October and here is the brief history-

 

First ride- Good! bike performed great, about four hours of desert riding.

 

-First oil change

-Spark plug change

-Rewired LED tail light using the blue/white wire under the seat as a relay trigger. 

 

Second ride- AZOP race, wouldn't start right away, required choke OUT to start, popped heavily on decel, surging on accel.  We ended up DNF after lap 2 because it stalled and wouldn't start.

 

-Second oil change

-Second spark plug change

 

Third ride- Bike behaves ok when cold.  Still a bit surgy/poppy.  After warming up it abruptly died mid 4th gear on the throttle to DEAD.  It behaves in a fairly predictable way.  Bike starts, runs poorly, dies after several minutes even at WOT.  Bike won't start for several minutes (5-8?) then all of a sudden it will fire and the timer starts again.  I get as far down the trial as I can before it abruptly stalls and the cycle repeats.  I've found that as long as it sits for a bit it will fire, even after running poorly and dying. 

 

-Changed oil again

-Change spark plug agian

-Removed the carb and cleaned EVERYTHING- it looked pretty good but I was very thorough.  Did a couple odds and ends (easy adjust Air/Fuel knob, verified throttle stop, repacked the muffler, etc) 

After reassembly the bike ran like a dream- for about two hours.  The idle started smooth and steady but after two hours of cruising around town stoplight to stoplight it went from 50mph steady throttle to dead.  After that it started a slightly offbeat idle again and died at a red light.  Now its suddenly behaving like it did before the carb cleaning.

 

Now I'm not sure where to go next! I'm now leaning towards electrical- stator? idk.  What do you think?

 

-Drew



  • Noobtastic14

Posted January 24, 2016 - 07:23 PM

#2

I feel like when I'm cruising and it dies it's as if the button gets pushed on the dash. Or if somebody turned the imaginary ignition key off. What would cause that?

  • GuyGraham

Posted January 25, 2016 - 05:05 AM

#3

Sounds like stator coil breaking down when it gets hot which is first symptom of a failing stator. I had this on another bike

  • Krannie McKranface

Posted January 25, 2016 - 06:18 AM

#4

Stator coil death

Debris in the tank getting into the carb

Corroded harness from stator at molex connection (very common)

Bad battery connections

Bad grounds

Clutch bypass switch shorting out

Kill button shorting out.

Improper fuel screw adjustment

Leaking hot start due to cracked cable cap

Partially clogged pilot jet passage above pilot (use fishing line to clear)



  • Noobtastic14

Posted January 25, 2016 - 09:52 AM

#5

Thanks for the reply krannie! (BTW your beta looks beautiful)

I looked at the stator but everything seems to be nice and tight and in place.

http://imgur.com/MHxzepm

http://imgur.com/SpNLWTQ

Where can I go to check for corrosion on the molex plug? Also, I think I'll follow the kill switch wires and look for a bad connection. This list gives me some focus which is great because I was getting mildly overwhelmed without direction.

-Drew

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  • GuyGraham

Posted January 25, 2016 - 10:25 AM

#6

Looking at the stator will not tell you if it is beginning to fail - it needs to be tested under load, and hot



  • Krannie McKranface

Posted January 25, 2016 - 11:09 AM

#7

Must test the stator per the service manual method with a multi meter

You can download a service manual on Yamaha's website

There is a stator harness plug you find by following the harness coming from the stator.

They regularly coroded.


Edited by KRANNIE, January 25, 2016 - 11:09 AM.


  • Noobtastic14

Posted January 30, 2016 - 06:57 PM

#8

Stator coil death

Debris in the tank getting into the carb

Corroded harness from stator at molex connection (very common)

Bad battery connections

Bad grounds

Clutch bypass switch shorting out

Kill button shorting out.

Improper fuel screw adjustment

Leaking hot start due to cracked cable cap

Partially clogged pilot jet passage above pilot (use fishing line to clear)

 

SOLVED!!

 

This was a pretty big pain in the ass.  I started with a simple fuel flow test- pulled the hose off the carb input and started draining it into a gas can.  After about ten seconds the fuel began to trickle less and was reduced to almost nothing.  That was actually a huge relief because it pointed me in the right direction.  I took off the gas cap and got normal gas flow into the carb.  The next step was replacing the one way valve located at the end of the hose.  After replacing the hose I still had fuel flow issues.  Next, I noticed that with the gas cap on I wasn't getting proper fuel flow but as soon as I broke the seal and removed the gas cap about 1/8 of a turn the fuel flowed fine.  Next step was removing the gas cap and blowing air through it- I was getting air but not nearly as much as I should have.  I flipped the gas cap upside down and removed the little cover.  I found a small chunk of dirt that was blocking the air from entering the gas tank!  After cleaning out the center of the cap and reinstalling it I all of a sudden got proper fuel flow to the carb and after about 30 min of hard test riding it never missed a beat ran like a champ. 

 

vKDKSu4.jpg

 

cN1KETw.jpg

 

Thanks for looking!

-Drew



  • Krannie McKranface

Posted January 30, 2016 - 06:59 PM

#9

Well duh.

 

That dirt clod was right where you left it.

 

You shoulda checked that first, huh.  :rolleyes:



  • Noobtastic14

Posted January 30, 2016 - 07:54 PM

#10

Right?!?! How did I not find that spec of dust on the first inspection?!?!?!?!

 

-Drew



  • AKmud

Posted February 12, 2016 - 03:22 PM

#11

Good find! Taking mental note now... :thumbsup:






 
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