07 valves sticking?


31 replies to this topic
  • rmracer27

Posted October 22, 2007 - 05:22 AM

#1

My bike has no compression right now. When you first kick it, it will have some compression then it goes to nothing at all. There is all kinds of air coming out of the breather hose and out the exhaust pipe. The bike has only got 14 hours on it. It did this one time before but after the 2nd kick it started working fine and run good all day. Has been running good until it sit for about 3 weeks. I'm really leaning toward the valves been stuck open. If thats what it is, what would be the best way to fix the problem? I'm thinking about letting yamaha know about it and go from there. I have talked to another guy and he said his done the exact same thing.

  • creeker

Posted October 22, 2007 - 05:26 AM

#2

Sounds like a stuck valve could be a real possibility... I think with it being an 07' I would let Yamaha know about it and go from there like you said.

  • grayracer513

Posted October 22, 2007 - 05:51 AM

#3

Have a leak down test done. That will pin down the point of the leak. Also, if a valve is really hanging open, the clearance on that one will be way big.

  • rmracer27

Posted October 22, 2007 - 06:49 AM

#4

Have a leak down test done. That will pin down the point of the leak. Also, if a valve is really hanging open, the clearance on that one will be way big.


What would be the best way of fixing it if thats what it is? The guy I talked to said he used wd40 and let it set for alittle bit. Then took something and pecked on the valve bucket. He said it has worked fine ever since. Just trying to keep from digging in 2 deep on a new bike.

  • grayracer513

Posted October 22, 2007 - 07:31 AM

#5

It depends on why it's sticking. The two most common reasons for this are rust forming on the valve seats while the bike sat for a while with the valves open, or carbon, either a chunk stuck on the valve face, or built up on the stem, keeping it from sliding up into the guide.

In either case, if the bike starts, it will likely fix itself. If it won't, then open the cam box up put the engine at TDC and check the clearances. When you find the one with way too much clearance, you've found your culprit. Then, CAREFULLY take a small punch, preferably brass or aluminum, and lightly tap the lifter so that the valve bounces open just a little and slaps back down on its seat. Stay on the lifter with your punch, and don't nick anything up. That should reseat the valve.

  • todds924

Posted October 22, 2007 - 05:05 PM

#6

It depends on why it's sticking. The two most common reasons for this are rust forming on the valve seats while the bike sat for a while with the valves open, or carbon, either a chunk stuck on the valve face, or built up on the stem, keeping it from sliding up into the guide.

In either case, if the bike starts, it will likely fix itself. If it won't, then open the cam box up put the engine at TDC and check the clearances. When you find the one with way too much clearance, you've found your culprit. Then, CAREFULLY take a small punch, preferably brass or aluminum, and lightly tap the lifter so that the valve bounces open just a little and slaps back down on its seat. Stay on the lifter with your punch, and don't nick anything up. That should reseat the valve.


I saw a WR 250 motor that had a piece of a cut zip- tie holding an intake valve open. It apparently got dropped in the airbox or intake tract while the carburetor was off and the motor sucked it up on start up. If you already hear air escaping , a leak down test will make this more pronounced, You will hear air escaping out of the pipe, carburetor, or both. A valve clearance check will tell a story also just as Gray suggested.

  • grayracer513

Posted October 22, 2007 - 07:20 PM

#7

I saw a WR 250 motor that had a piece of a cut zip- tie holding an intake valve open.

:crazy:

Reminds me of the time I discovered someone had left a shop towel or two in the extension housing of an automatic transmission.

  • 642MX

Posted October 22, 2007 - 07:41 PM

#8

My bike has no compression right now. When you first kick it, it will have some compression then it goes to nothing at all. There is all kinds of air coming out of the breather hose and out the exhaust pipe. The bike has only got 14 hours on it. It did this one time before but after the 2nd kick it started working fine and run good all day. Has been running good until it sit for about 3 weeks. I'm really leaning toward the valves been stuck open. If thats what it is, what would be the best way to fix the problem? I'm thinking about letting yamaha know about it and go from there. I have talked to another guy and he said his done the exact same thing.


I thought my 426 had the same problem a few months ago (a valve stuck or something). I kicked it over and it had very little compression. And then I remembered that I put new grips and a new throttle tube on. In the process, I guess I flooded the motor enough to wash the rings out. A drop of Rotella in the spark plug hole restored the compression and it fired right up.

Maybe someone has been twisting your throttle? :crazy:

  • rmracer27

Posted October 23, 2007 - 03:41 AM

#9

No one has been twisting the trottle since I'm the only person around it. I'm going to call yamaha today and see if they want to take care of it. If not I'm going to do it. I'm leaning toward a stuck valve.

  • rmracer27

Posted October 24, 2007 - 03:17 AM

#10

Taking the bike to the dealer today. Yamaha is going to help out on this problem.

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  • rmracer27

Posted October 26, 2007 - 03:47 AM

#11

The dealer took the bike apart and they are saying it had 2 broken exhaust valve springs. I'm kinda thinking BS since the bike was running fine when I shut it off. They said it had a lot of carbon build up and the springs are broke due to high revving! They are replacing the exhaust valves, Springs, piston,and rings. Yamaha is covering everything except for the labor. They said they cleaned up the valve guides also since the valves wasn't traveling good in them. I'm going to call back today and ask alot of questions. Things are not making since to me.

  • grayracer513

Posted October 26, 2007 - 08:45 AM

#12

What it sounds like to me, as someone who spent over twenty years repairing stuff under one warranty or other, is that there are two stories being told; the 'official' story they're telling you and Yamaha to get the repair done under warranty, and the truth, which is that the bike had a valve sticking open from carbon on the valve stem. The part that sounds fishy is that they want you to pay the labor. Getting the labor paid should have been the point of BS'ing the factory in the first place, and you shouldn't be paying it if that's the case. If it was carbon, and they were going to charge you for it (which they should have), then why the story about the springs?

As a Yamaha warranty rep, I would want to see the springs. So should you. Something doesn't add up.

  • todds924

Posted October 26, 2007 - 03:47 PM

#13

What it sounds like to me, as someone who spent over twenty years repairing stuff under one warranty or other, is that there are two stories being told; the 'official' story they're telling you and Yamaha to get the repair done under warranty, and the truth, which is that the bike had a valve sticking open from carbon on the valve stem. The part that sounds fishy is that they want you to pay the labor. Getting the labor paid should have been the point of BS'ing the factory in the first place, and you shouldn't be paying it if that's the case. If it was carbon, and they were going to charge you for it (which they should have), then why the story about the springs?

As a Yamaha warranty rep, I would want to see the springs. So should you. Something doesn't add up.


Lets eyeball those springs!!!! If yamaha is repairing it under warranty, they would also cover the labor. How did they "clean up" the valve guides? Man, i wanna see these parts and cylinder head.

  • sirthumpalot

Posted October 26, 2007 - 04:17 PM

#14

I'm on an 01' 426 (feeling obscelete now), but I've had the no compression issue several times, and it always goes away after I kick it a few times and it fires up. I can recreate the issue 100% of the time by putting some carb cleaner through the fuel screw opening (and therefore into the motor). If I squirt enough then presto zero compression. Like absolutely zero. I don't know why, my best guess is no oil on the cylinder walls? Anyway, a few kicks and it fires and is instantly better. So I'm wondering if it's something similar that was happening to your bike?

  • rmracer27

Posted October 26, 2007 - 07:15 PM

#15

I'm going to try to get them to let me see the parts and if I can I will get some pics. I just don't think the valve springs were broke. Don't know how they cleaned up the valve guides. I talked to the service manager today and he got alittle mad when I started asking several questions. For one was how was the bike running fine when I shut it off with broken exhaust valve springs? The answer was oh i thought the bike stopped running. LOL

  • 642MX

Posted October 26, 2007 - 07:20 PM

#16

I'm going to try to get them to let me see the parts and if I can I will get some pics. I just don't think the valve springs were broke. Don't know how they cleaned up the valve guides. I talked to the service manager today and he got alittle mad when I started asking several questions. For one was how was the bike running fine when I shut it off with broken exhaust valve springs? The answer was oh i thought the bike stopped running. LOL


Maybe you should stop by the shop and see whats going on. From what your saying, I wouldn't trust there word.

  • rmracer27

Posted October 26, 2007 - 07:25 PM

#17

Maybe you should stop by the shop and see whats going on. From what your saying, I wouldn't trust there word.


The problem is they are lancaster, oh and I'm 2 hours away. They came and picked up the bike for me since I bought it off them. They are well known dealer around here. The local dealers are very crappy around here in WV.

  • 642MX

Posted October 26, 2007 - 07:30 PM

#18

The problem is they are lancaster, oh and I'm 2 hours away. They came and picked up the bike for me since I bought it off them. They are well known dealer around here. The local dealers are very crappy around here in WV.


They drove 2 hours to pick your bike up?....Wow, thats good customer service. But, I don't trust dealers, I'd make the trip.

  • snoplw

Posted October 26, 2007 - 07:36 PM

#19

I would say that the dealer is full of it on the springs i had a 07 yam yz 450 and the same thing happened. it was exhaust valve on the pipe side I would kick over air coming out of breathers . I took it apart the valve had stuck open lucky i was going to top for a good kick because when i did this valve went full open piston tapped valve back up enough for small bend. no damage to piston replaced both exhaust valves springs keepers. the valve looked rusty i think yam has low quality ti valves to look rusty. i did a mud race washed bike fired up placed in traiker sat 3 days stuck. i fixed myself runs great. rember these 4 strokes are nothing more than glorified briggs. easy fix. i am a proud owner of a husky tc now love it.

  • rmracer27

Posted October 26, 2007 - 07:41 PM

#20

I'm going to call tomorrow and talk to the owner about whats going on. Hopefully they will pay the labor also. They labor is only for 4 hours, but still I don't think I should pay it.





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