random stall


4 replies to this topic
  • harleyrob2000

Posted April 20, 2009 - 12:46 PM

#1

I have a 08 yz405f. Stock jetting. Valves in spec. I have about 25 hours on it. The bike just randomly stalls about once every 30 min or so of trail riding. I am not stalling the bike... today I was going over a double log crossing and right in the middle it just sputtered out. I didn't hear a pop or a cough. I ride trail in florida.

Any ideas would be appreciated.

  • grayracer513

Posted April 20, 2009 - 12:52 PM

#2

Pull the fuel line off at the carb and open the petcock with the fuel line draining into one of your gas cans. If it starts out fast and then slows a lot, or stops flowing , gurgles, and restarts, your tank cap or vent line is obstructed (be sure the inline valve is facing the right way).

When it dies, does it restart easily/immediately? Or does it take a while to "get over it"?

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  • harleyrob2000

Posted April 21, 2009 - 03:10 AM

#3

I pulled the fuel line. It poured smoothly and didn't gurgle at all. I pinched the vent line and it slowed and stopped. I let go of the vent tube and it resumed normal flow.

If I kick it immediatly after the stall it takes about 5 kicks to start it. If I wait 5 seconds, it seems to fire on the first kick.

  • grayracer513

Posted April 21, 2009 - 06:41 AM

#4

I pulled the fuel line. It poured smoothly and didn't gurgle at all. I pinched the vent line and it slowed and stopped. I let go of the vent tube and it resumed normal flow.

If I kick it immediatly after the stall it takes about 5 kicks to start it. If I wait 5 seconds, it seems to fire on the first kick.

Your problem may be electrical. The trouble is that it's intermittent, and may not "stay broke" long enough to diagnose by an ohmmeter. If I had to guess based on reports I see, I'd say a stator was at fault.

What you can do, though, is check immediately when it stalls out to see if it has spark.

  • gdbarr1976

Posted April 21, 2009 - 08:11 AM

#5

Make sure you have plenty of play in the hot start cable. Mine was stalling in random turns. With bark busters mounted to the triple clamps my number plate was pushed out just enough that when I ran the hot start cable throught the holder on the plate it would take all the play out so when I turned it would open the hot start just enough to stall. To fix it I just have it run loose as in not throught the holder thing on the number plate. I also run higher than stock bars which could have also made the problem worse.





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