my 2004 400ex blew up
Mar 29, 2005 | 01:17 PM
#41
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my 2004 400ex blew up
There are other uncomon things that will cause it, but the must common is dirt. The grit just sands away the piston and cylinder. .008 will cause a skirt to brake.
The grit is so fine allot of times the piston and cylinder will be smooth right down to the brake in the piston.
The grit is so fine allot of times the piston and cylinder will be smooth right down to the brake in the piston.
Mar 29, 2005 | 01:24 PM
#42
T Rex Rider
What irritates me is!
Those 6-packs work pretty good.
What irritates me is!
Those 6-packs work pretty good.
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From: Oeste Del Tejas
my 2004 400ex blew up
Originally posted by: Harw
There are other uncomon things that will cause it, but the must common is dirt. The grit just sands away the piston and cylinder. .008 will cause a skirt to brake.
The grit is so fine allot of times the piston and cylinder will be smooth right down to the brake in the piston.
There are other uncomon things that will cause it, but the must common is dirt. The grit just sands away the piston and cylinder. .008 will cause a skirt to brake.
The grit is so fine allot of times the piston and cylinder will be smooth right down to the brake in the piston.
Mar 29, 2005 | 01:57 PM
#43
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my 2004 400ex blew up
Originally posted by: Raptorlegs
I just think there would have been other evidence to support foreign debris or predetonation.
Originally posted by: BigBlack
Also incorrect piston/cylinder fitment could cause this too in addition to your previous comments.
Also detonation prior to top dead center will cause the piston to rock having tow forces acting in opposite directions putting a lot of pressure on the skirt trying to keep the piston straight which can also cause skirt failure but detonation generally cause others problems before the skirt has time to be a problem.
Originally posted by: Harw
The piston skirt brakes from too much piston to cylinder wall clearance. The piston rattles at the bottom of the cylinder and breaks the skirt off. The most common cause is the motor digested a lot of dirt through the air intake.
The piston skirt brakes from too much piston to cylinder wall clearance. The piston rattles at the bottom of the cylinder and breaks the skirt off. The most common cause is the motor digested a lot of dirt through the air intake.
Also detonation prior to top dead center will cause the piston to rock having tow forces acting in opposite directions putting a lot of pressure on the skirt trying to keep the piston straight which can also cause skirt failure but detonation generally cause others problems before the skirt has time to be a problem.
I just think there would have been other evidence to support foreign debris or predetonation.
Mar 29, 2005 | 02:45 PM
#44
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my 2004 400ex blew up
I wasn't triing to discredit the dirt or engine mod theory just that for it to happen so soon it might of had a flaw in the piston. It happened on my bike and it also happened to my friends 87 250R. The dealer triied to say I did something wrong. At that point everything was done per manufacturer specs. I only had 15 hours on it. They eventually fixxed it without admitting it was a defective part. Same for the 250R, it had more hours though.
Sorry if I offended anyone.
Sorry if I offended anyone.
Mar 29, 2005 | 03:36 PM
#45
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my 2004 400ex blew up
Originally posted by: JkAss
I wasn't triing to discredit the dirt or engine mod theory just that for it to happen so soon it might of had a flaw in the piston. It happened on my bike and it also happened to my friends 87 250R. The dealer triied to say I did something wrong. At that point everything was done per manufacturer specs. I only had 15 hours on it. They eventually fixxed it without admitting it was a defective part. Same for the 250R, it had more hours though.
Sorry if I offended anyone.
I wasn't triing to discredit the dirt or engine mod theory just that for it to happen so soon it might of had a flaw in the piston. It happened on my bike and it also happened to my friends 87 250R. The dealer triied to say I did something wrong. At that point everything was done per manufacturer specs. I only had 15 hours on it. They eventually fixxed it without admitting it was a defective part. Same for the 250R, it had more hours though.
Sorry if I offended anyone.
Mar 29, 2005 | 05:07 PM
#46
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my 2004 400ex blew up
I can't help it I have to reply. I'm going to say everyone is right here and unless we tore the engine apart theres no way to tell. I see now that a skirt can be defective. All of the engines I have seen untill now had blown up much worse and I had never considered the skirt to be the start. I always thought it was from the rod hitting it or being blown down into the crankshaft.
As far as the piston being held straight by the skirt that is nonsense. The rings center the piston and their should be no contac between piston and cylinder wall other than the rings. This is one reason I recommend a full throttle break in instead of the factory recommended one. It seats the rings perfectly and this problem never happens.
I have a question to the guy with the 250r. Was your engine still running when the skirt was discovered to be broken? DId the rod, wrist pin or crankshaft break? If not what happened and how did you keep from ruining the rest of the motor and determine where the failure occured?
If I am wrong I am sorry. I apologize for giving out dissinformation and will stop posting on the forum.
As far as the piston being held straight by the skirt that is nonsense. The rings center the piston and their should be no contac between piston and cylinder wall other than the rings. This is one reason I recommend a full throttle break in instead of the factory recommended one. It seats the rings perfectly and this problem never happens.
I have a question to the guy with the 250r. Was your engine still running when the skirt was discovered to be broken? DId the rod, wrist pin or crankshaft break? If not what happened and how did you keep from ruining the rest of the motor and determine where the failure occured?
If I am wrong I am sorry. I apologize for giving out dissinformation and will stop posting on the forum.
Mar 29, 2005 | 05:23 PM
#47
Monkey Rider
Afro-Engineer
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From: The Asphalt Jungle
my 2004 400ex blew up
Originally posted by: ixRAZORxi
....
If I am wrong I am sorry. I apologize for giving out dissinformation and will stop posting on the forum.
....
If I am wrong I am sorry. I apologize for giving out dissinformation and will stop posting on the forum.
On another note you will not convince me that a K&N with an Outerwear and properly maintained is harmful for the motor. Maybe we dont have dust in the NW or sompin i dunno. but ive ridin and drivin allotta hours and miles and all my vehicles and toys have em. and never had a problem. However i did have a wrist pin clip come off a piston one time and the wrist pin backout out and bent the ear on the piston and it was slamin into the head. i still rode it 7 miles outta the woods mesed up. but man did it sound bad. That piston sits on my desk as a paper weight now. I look at it sometimes and wonder if i didnt get it balanced when i carved on it to clear my valves or sompthing. I dont know why it came loose [img]i/expressions/face-icon-small-sad.gif[/img]
Mar 29, 2005 | 05:34 PM
#48
T Rex Rider
What irritates me is!
Those 6-packs work pretty good.
What irritates me is!
Those 6-packs work pretty good.
Joined: Jun 2003
Posts: 16,801
Likes: 1
From: Oeste Del Tejas
my 2004 400ex blew up
Originally posted by: ixRAZORxi
The rings center the piston and their should be no contac between piston and cylinder wall other than the rings.
The rings center the piston and their should be no contac between piston and cylinder wall other than the rings.
The skirt can rub. Especially upon a cold start up. Ever hear the term piston slap?
Mar 29, 2005 | 05:49 PM
#50
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my 2004 400ex blew up
Luckily, if it can be considered luck the broken part of the skirt wedged between the crank and the case when I was kicking it over, I kicked over about 5-6 times, if my memory is correct(its been a few years since then) before it seized up competely. Therefore minimalizing how much debris got into the crankcase. So it never did get started. It didn't crack the crank case. The damage to the crank case parts were fairly minor replaced brgs and seal. All the other parts were OK. The damage would have only really mattered if I had to pay fot it. Thank god for warrantees. As far as figuring out what happened and this why they said they would not honor the warrentee is because I pulled the top end off myself and found the problem. I guess they rather hide their problems than have people find out what was really wrong. After I kept bothering the dealer and Suzuki they finally agreed the honor the warrentee. The squeeky wheel gets the oil.