426 won't start 24 hrs after riding it.. (Help Needed)

19 replies to this topic
  • Turf_Runner2

Posted July 01, 2004 - 07:28 AM


I rode Monday evening with no problems. Went home adjusted the bars and levers that night with no problems. The following evening I went out to start it and could not get it started. I waited a full hour with no luck. Got pissed put the bike away and tried again last night with the same results.

I have not added any gas since it ran Monday night and I have followed my normal routine for starting it. I typically starts with a 4-5 kicks cold.


  • John_Lorenz

Posted July 01, 2004 - 07:48 AM


change the plug

you can see if it is getting gas.

Chances are you flooded it and fouled the plug

  • bushy

Posted July 01, 2004 - 07:55 AM


If you adjusted the bars your decompression lever may be slightly opening the exhaust valve.

  • rush66

Posted July 01, 2004 - 07:55 AM


if you adjusted your bars and levers and after it wouldn't start afterwards check and see if your kill switch is ground

  • Turf_Runner2

Posted July 01, 2004 - 09:30 AM


How do I check or remedy a stuck exhaust valve?


  • John_Lorenz

Posted July 01, 2004 - 10:05 AM


How do I check or remedy a stuck exhaust valve?


He is refering to if you adjusted the decomp lever and it is to tight and holding the valve open.

Simple turn the bars from full lock to full lock right to left while looking at the decomp lever at the Valve Cover

You will see it move

Are you sure this is the case, if it is stuck you would be able to turn the motor over with your hand (NO COMPRESSION)

  • Ga426owner

Posted July 01, 2004 - 11:34 AM


When were the valves adjusted last?

  • sirthumpalot

Posted July 02, 2004 - 02:58 AM


Change the spark plug. If ever a previously fine running YZF (at least the 426 models) don't start after a handful of kicks, then change the plug before you do anything else. I used to have this problem (ran fine, 24 hours later needed a new plug). In my particular case it was caused by 2 things. 1) Using gas from the local Mobil station would do it to me every time, 2) starting it to show a buddy, running it for only 20-30 seconds then turning it off. Running it until it's full temp and not using Mobil gas has 100% cured the problem in my particular case, hope this helps.

  • Merfman

Posted July 02, 2004 - 04:04 AM


Is the 426 an '01 or '02? If so, 110% agreement with Sir T-alot. My 01 had exactly the same symptoms. You've likely fouled a plug.

If you have, change gas. The culprit in my case is our crappy oxy-fuel. It has NEVER fouled a plug like this when I've used good (race) gas.


  • oldbones

Posted July 03, 2004 - 03:15 AM


When you were fiddling with your bars and controls, you probably inadvertantly twisted the throttle a few too many times and filled 'er with gas.

Change/clean the plug... :thumbsup:

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  • bushy

Posted July 03, 2004 - 04:09 AM


How come the 426's dont start easy after blipping it. I can blip mine all day and it will start right up :thumbsup: And yes my pump works.

  • RJB

Posted July 03, 2004 - 04:40 AM


Blipping with the engine off will flood and kill mine every time. I think you might be referring to blipping it while engine running?

  • Turf_Runner2

Posted July 06, 2004 - 09:13 AM


It's an 00 and I've had it with this bike!!!

I changed the plug with no luck and gas is good. Valves were adjusted 12 months ago.


  • John_Lorenz

Posted July 06, 2004 - 09:32 AM


12 months?

How many hours of riding is that?

20 hours 40 hours 60 hours

Are you sure you are getting sparc?

  • Turf_Runner2

Posted July 06, 2004 - 10:18 AM


Maybe 15 hours total.

  • cbff33YZ426

Posted July 19, 2004 - 08:37 PM


I have a 00 426. a month ago. I was out on an 8hour ride. she ran like a champ. Next day,,,Dead as hell. here are some tricks. I friend of mine who is a mechanic for yamaha told me something that goes against what you will be told here, and in books. Choke it...open the hot start button, pull your throttle WIDE open and hold it there....start kicking...after two day of not being able to get it to do anything,,,I did that...and in four kicks...she was running with no problems. If you get your jetting right...you can go months without changing your plug. You could have on overly rich condition after you store your bike after a ride. opening the choke, and hot start switch give more air to the carb, and holding the throttle wide opens the accelerator pump allowing more air in. Give it a try if you have the problem again.


Posted July 20, 2004 - 05:51 AM


Lots of stuff to deal with here..... Have you tried somthing as simple of turning up the idle knob a turn or so and try it again.

My 426 tends to get stubborn sometimes. Ill ride all day in the heat and my idle will creep up and I'll turn it down as low as I can get it. If I forget to turn it back up when the motor is cold, it will never start.

Just a thought.

Bonnzai :thumbsup:

  • YZ426FPilot

Posted July 20, 2004 - 06:31 AM


Pulling in the compression release, kicking it over about 10 times or so with no throttle, pulling out the hotstart & the choke has always worked for me.

Keep in mind that strait fuel (not premixed) really doesnt foul plugs, oil does. If a plug is wet with fuel it will evaporate eventually allowing spark. The only time a plug will stay "fuel fowled" is if you have a excessivly rich condition drenching it with fuel.
Once a plug is oil fowled its prety much useless, and all the kicking in the word will not bring the motor to life.

  • Turf_Runner2

Posted July 20, 2004 - 07:25 AM


I feel like a Jack Ass. The damn decomp cable was loose on the mounting braket on the engine block.

I suck.

Thanks for all the help guys.

  • YZ426FPilot

Posted July 20, 2004 - 08:10 AM


Look at the bright side. You'll never have to worry, because you wont let that happen again! :thumbsup:

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